Yoga Passage is indeed as good as Yoga Studios get. As someone who finds some Yoga places a bit too pretentious for me to feel comfortable, I find Yoga Passage the perfect mix of dedicated to the art of Yoga, but not overly commercialized or at all judgmental.
I've been going to Yoga Passage for about three years now, off and on. They offer a great variety of classes and have great walk-in rates. Their Karma Yoga on Sundays at 1pm (by donation) are usually a lot of fun and packed to the gills.
Overall, I have nothing but kind words about Yoga Passage. You should check it out for yourself if you're in the area - and if you're not - it's worth the walk/drive!