I have a pass at Steven's this year and I'm really getting excited. I've never ridden the Rockies but I have ridden Hood quite a bit and love Steven's almost as much as I love Mt Hood Meadows. The park probably isn't the biggest you've ever seen but it is serviced by its own lift and has small, medium and large features that are well laid out and spaced. We have some pretty steep double blacks, more than one in the 60 degree range which feels downright vertical. The backside of Steven's has some pretty long runs through some nice in-bounds back country feeling untracked areas. There are a lot of nice tree runs if that's your thing. The powder early season and in the spring is a bit wet and heavy but there are some days mid season where its light and fluffy, less so than in the Rockies I'd bet but I can't really compare having never been. The only other real option in my opinion for Seattle riders is Crystal and as far as I remember they don't have a park but they do boast a ton of in bounds back country riding, finally lift serviced. Snoqualmie can be fun, so I hear, but its low elevation and total vertical kind of puts me off and I haven't visited. I hear they have a good park, or several good parks, not really sure.
I'm heading up to Mt. Baker in the morning since Steven's isn't going to be opening this weekend. Looking forward to next weekend when, I'm pretty sure, they'll finally be open.