Thanks for the .02. I'm 5'9", so not exactly tall. I've had a hard time finding much support for 650B in the area (north of Boston). Everything that the shops have with that wheel size are more aggressive trail bikes than I'm interested in. I've been really impressed with the 29er bikes that I've tried, especially giving that I don't feel like the handling isn't something that I could get used to. It's different than my 26" bike, but not unmanageable.
Give then choice, I would pick fast and flowy. Of course, I have to deal with what the trails are like in the area, so rock gardens and roots.
I agree that testing is important, so it's a drag when shops can't help you figure out a way to test a bike. So I'm really leaning towards the bikes that I can test.
Pretty sure that I'm going with the Tallboy, based on the ride, the positive vibes that I've heard about the bike and SC's reputation for building really tough bikes.