I just bought one! Turned out Johnson String Instrument is local, so I went and checked out all three models. Took my guitar and support to test-drive them, so to speak. I got the one above -- the heaviest at ca 12 lbs, but by far the most stable, and with the best seat. It has just the right amount of cushioning, not too much, but enough.
The two models with the hardwood seats were much lighter though. The one that is infinitely adjustable is a great concept, but was a little tippy, even for me, so I think a tall guy would have a problem with it. The seats were actually a bit narrower, not as comfortable: they'd be good if you needed to carry your chair with you, but not for long-term practice. The one above seems suitable all-around.
Of course I'll know more when I spend some time practicing on it later today.
2015 Connor spruce/Indian rosewood
1978 Ramirez 1a cedar