I've been training in Seattle since 2012 now.
I first checked out Marcelo Alonso's and Gracie Barra. I had very positive experiences at both gyms. MA's was very friendly and inviting. When I visited, they were preparing for a tournament, so everyone was just doing live positional drilling. GB's facility is dope, and there is a wide variety of training partners with high skill.
I ultimately joined Mat Chess MMA (very close to the University of Washington). I originally was apprehensive to check it out because I wanted to find a gym with a focus on BJJ (not MMA0, but the instructor, Andrew Perkins, is a total beast on the mat in every position. He's a black belt under Dave Ginsberg (Mario Sperry BB). He is a big guy -- 215-220 lbs -- with an absolutely sick, dynamic bottom game. He has a very strong butterfly, x-guard, and omoplata game and a
very hard guard to pass. When he is on top, the pressure passing is a nightmare. Also, Andrew trains with all his students. In my near 7 years of training, no one has wrecked me the way Andrew has/does.
Mat Chess has a cool grappling schedule with no-gi on Monday, Wednesday, and Friday and wrestling followed by gi BJJ on Tuesday and Thursday. Open mat is Saturday. On Sunday's, Andrew has an open door policy to all other brown/black belts in the Seattle area to come in to train. We have a wide variety of training partners of different sizes and styles -- tons of blues, several purples, and a couple brown belts.
Conclusion, there are many great options for BJJ training in Seattle. Personally, I've had a great experience at Mat Chess MMA and have felt my game reach a new level due to the training I've received there.
http://www.matchessmma.com/