I personally just used Walmart's photo center, simply because it was cheapest and they had a convenience online tool and delivered to my door. But for the canvas prints, I had to make minor edits to stretch the edges, since the canvas has wrap around (and I didn't want a plain white edge). That's not an issue if not using a canvas format.
You might be able to get higher quality from other printers, though at a higher price. I did try some other possible printer that would have avoided the need to edit the images (they had a mirror option for the canvas wrapping), but it was significantly more expensive, so I didn't do that.
Also, I think @user@domain, but I don't know if it notifies the user yet.
I’ve been getting large canvas prints (40x20inch - large to me anyway) from easycanvasprints.com for several years now and have been really impressed with each one. And the price is never bad at all.