Like anything else, depends how it is used and how it looks. Games like genshin impact and granblue fantasy versus barely look cgi/3d. You can tell it's cgi, but it'll be easy to forget it's cgi.
But then you have cgi that's just very obvious. I notice it mostly with anything vehicle or mech based. The drill in avatar the last Airbender, space ships, cars, etc. Often times these things are so noticeable against the 2d environment that it takes you out of what you're watching. It's better today, the cgi mechs were less glaring in legend of korra as an example. But it can be difficult to make them "blend".
I think we are at the point we can make cgi look like anything we want. Puss in boots the last wish barely felt cgi with its painterly style, textures, lower fps, and 2d backgrounds. We don't need everything to look like disney/Pixar. I think it would be neat to see an anime in the classic anime/etc style that is fully 3d/cgi. Beastars is an interesting anime and style but it doesn't "feel" anime. It feels much more "western" in vibes, style, etc so I have trouble counting it.
I don't care if it's animated in 2d or 3d, I just want it to look good. And cgi doesn't automatically make the anime look bad.
What usually makes an anime look bad is obvious cgi used in an otherwise 2d anime. Not always though, Fate/Zero's Berserker is an example of obvious cgi that looked good.
I don't really mind full cgi anime. I'm loving the current Kamierabi, for example. But they look off to me for the first half or full episode before I get used to it. Even Houseki no Kuni was like that. There are of course bad looking full cgi anime, but in general they don't look worse than 2d anime to me.
I also don't mind cgi backgrounds in 2d anime. Dekiru Neko looked amazing and the backgrounds definitely contributed to that, not the opposite.
If it's done as a time/cost saving measure, I don't like it because it usually shows. It rarely matches with the 2D animation both stylistically and in movement. It looks better in one anime, and worse in another, but I usually prefer 2D either way, especially for things in the foreground. For example, MAPPA's AoT 3D looks pretty good compared to most other anime, but you can still really tell, unless they stop moving. They feel weightless otherwise and move in a way that don't match 2D movements.
If it's done with 3D in mind from the start because it's 3D and not to replace 2D, like Land of the Lustrous, then I think it's great, because then they use the strengths of 3D animation instead of just seeing it as a cheap replacement for handdrawn 2D animation. Land of the Lustrous is still one of the prettiest anime to date in my opinion, because you can tell the studio cared about its 3D.
Like any artistic tool, it can be used to great effect but it can also be done shitty too.
People think of CGI as 3D models but it is so much more than that. It also includes lighting and physics engines. It enables things that either cannot be done manually or are too laborious to do for every single frame of an anime.
Used well, it can really enhance scenes with things like animations of background elements like grass or lighting effects. Used poorly, it can really pull you out of the scene.
What do I mean by poorly? Well, when you mix and match manual animations with CGI without considering the nature of both, would be a good start, and something that many anime are guilty of.
Manual animations are very approximate and choppy, with clear distinctions between key frames that are obviously meant to be the focal point, and tween frames that are transitional. Manual animations hang on to their key frames longer than the tween frames, even if there are slight alterations (eg: mouth movements) between one frame and the next.
CGI animation is very precise and smooth, and animates much more mechanically. It has no concept of a key frame, and moves from A to B in a perfectly consistent speed, in a mechanical way. Even if the animators cap the framerate to 25fps, the difference in movement is still obvious if that's all they've done. Same goes for lighting too, switching from 2D manual shading to 3D automated shading can be really obvious.
There are ways to eliminate this problem, but it takes great care and planning with regards to art styles in order to do it correctly.
Personally, I very much dislike it. I'm willing to forgive/tolerate it when shows use it for a few scenes or complex models, but I'm not really interested in watching anything that is fully CG. Too me, hand drawn (especially cel) stuff has a certain beauty to it that is just simply unmatchable by any CG stuff that I've seen.
I miss the 80s/90s handmade look. The new school of CGI (Spiderverse, Last Wish, TMNT) are an improvement and good in their own right, but they don't scratch my itch for handmade animation.
The CGI is kind of jarring for me when used along with traditional animation. It's such a stark contrast of smoothness of animation that it detracts from the experience for me. So I'd say either CGI or traditional, but not both.
CGI can look absolutely stunning if it's done right, and even mediocre CGI isn't a reason for me to dislike an anime. It has to be a special kind of awful to make me stop watching.
I don't like it at all. I know sometimes it's hidden and small scenes can get away with it, but I generally don't like it because mostly it's done cheap. It almost ruined Attack on Titan for me, thankfully I stuck with it as it's amazing. I couldn't watch Beastars or this horror one everyone likes. I could deal with land of the lustrous for a bit but got bored, because the art style, while magnitudes better than most cgi, still looks worse in my eyes and than the story needs to be extraordinary good to balance it. I can't unsee most cgi no matter what. Good cgi is still noticable to me, even if the art style stays the same, my brain can tell by the complexity of the scene and how hand drawn they'd have done it in a different way. I however like full cgi, like Zoomania.
It's almost always done poorly, and it's really hard for me to get into a fully CG anime because of this. Part of the point of watching anime is for the animation and CG tends to be very poorly animated (the models tend to be too rigid and they often artificially lower the framerate across the board instead of selectively like with hand-drawn).
Like anything, it has limitations and strengths which need to be accounted for. Land of the Lustrous might be the only CG anime that I wasn't just thinking it would've been better with traditional animation.
When used for specific parts of a 2D anime it's hit and miss too, but again that's an error in execution. It does seem like mediocre CG looks worse than mediocre 2D, so that doesn't help either.
So there are anime that has full CGI and the one that use it for complicated scenes. For the full cgi anime, they often look quite cheap, the reason CGI is more expensive than drawn thing and they don't have the budget to make it properly. Usualy i don't like it. And for the anime that only use in in certain cases is hardly depend of the quality. Still it's often quite low as again, CGI is more expensive. So you clearly see when it is used, it destroys imersion and just look bad. But in a few cases, that are seldom it looks alright and i understand why they used in in that place. I clearly prefer if they refrain from using it, but at the end it hardly depends on the outcom and if it looks good, i don't care about it.
I mostly hate when they mix 2d and 3d, it always stands out too much. Like the tanks in the original avatar series, or when mappa started animating AOT and used 3d on the titans. I think if you stick with 3d for everything, it can be pretty good
Mostly annoying, largely because it looks very stuttery to me. When it's integrated seemlessly, it's fine (more often the case for background related cgi). Even in something like chainsaw man which did it pretty well I still found the cgi in the action scenes grating, it took me out of it a little.
Full cgi i mostly get annoyed at the stutter, and I like the style most full cgi anime have a lot less than most 2D anime.
Honestly, I think that making a distinction based on the tools used to create an anime is asinine.
The only things that matter to me are whether or not the art fits, and whether or not it's well executed. I couldn't care less if it's 100% hand-drawn or 100% CGI or anything in between - if it's well executed and appropriate to the anime, then it's good, and if it's not then it's not.
It was the first one I saw that tried mixing drawn and cgi and for the first few minutes of car footage I was like “huh, look at what they’re doing now. At least I think that’s what I’m seeing here.”
Definitely was a little rough and took some getting used to, but a fun ride. Now and then I’ll still sit down to watch the tofu delivery guy nonchalantly drifting down the mountain.
Apart from beastars making the rabbits look totally different from the original work, and just off looking in general, no major complaints as long as it doesn't look super incongruent or anything. I can't actually think of anything else off the top of my head that bothered me about 3d use in any show and that was just a poor design choice that could have been done in 2d as well.