I like it!
I'd recommend getting the 488mkII. I don't have a huge amount of experience with it, but I do own one, I've used it, and I think it's great. It's the same design factor as the 424mkII, which is one of my favorite Portastudios, ever. It's pretty sturdy, overall, and I've not had any problems with buttons or anything else. I am gentle, and baby my equipment, in general, and I never press buttons with a heavy hand, but not because I think any part is weak, just because that's how I treat my equipment.