I haven't been to Baker or Stevens but have spent a significant amount of time at Snoqualmie and Crystal.
Alpental is amazing, it packs a lot of craziness into a tight package off chair 2 and since it's smaller you can get more repetition or mix-it up a lot more. It also has a nice little back country area that's really fun.
I definitely loved Crystal too!
If you're on vacation, at least Snoqualmie and Alpental are way closer to Seattle if you want things to do away from the mountain.