I’ve hosted something or other at most of the restaurants with space. Starting from downtown and working outward: If you have a very large group, Maggianos has the best facilities and parking, service and food. I don’t think anyone else is nearly as good for scale. For the next step down in size, but up in quality, El Gaucho. Most of the restaurants can be booked out. Best food is pretty clearly Seastar, but they have constrained space – although they can take over the conference room on the first floor and that will suit a decent crowd. The facilities at twisted cork (or whatever it is called now) are awesome, and the kitchen is fairly good, and it’s locally owned so you can get attention and care. I would recommend the Bellevue Club, and … what’s the other one…. right downtown.. Can’t remember the name. Barking Frog if you can get it. Pomegranate in Bellevue is the top caterer on the eastside in my opinion, although Seattle has plenty to offer. So you could get a hotel (cheap) then hire Pomegranate. I won’t recommend the hotels – they’re universally bad. Outside of town the winery is popular (but good luck with that) and my favorite facility that I always recommend is Newcastle golf course. Especially for brunches. But booking it out is something that you have to compete with
I can’t recommend downscale, because I don’t use it.
Hope that helps.