It's not for everyone, but if it's for you, it's amazing.
I'd highly recommend beating the base game first if you haven't already. The complexity really ramps up quite a bit, so if you struggle with the base game, it might be better to hold off. That said, if you're confident in your problem solving skills and willing to push through some of the tougher bits, you could totally jump right in to Space Age.
I think I'm at around 100 hrs in to SA so far, and maybe (optimistically) half way through, and I've loved every bit. Except Gleba, fuck Gleba. :)
Shit man I hardly get trains and I got the half amount in the base game. But I refuse to watch tutorials or read because that just takes away the fun. You sold me, I like to support the devs and having even more fun to sink time into is amazing
Tbh I probably never need another game!
I will warn you, it'll push your requirement for understanding game mechanics, and make you solve problems in new ways from the base game. It's also not feasibly beatable without at least some understanding of circuits, logistic mechanics, and (space) trains.
That said, good luck, and may your factory grow in perpetuity!
Seriously though it's really well thought out actually. Each planet has unique challenges you will have to deal with and it's clear they put a lot of effort into designing these challenges and their solutions. Each planet grants new features that give you options you wouldn't otherwise have to help solve other problems. Lots of quality of life changes and an ever-improving user experience.
It won't win over people who didn't like Factorio but fans of the game will get more of what they love.