I really like the clean simple look of the Fabric water bottle system, so I bought 2. I did not have an issue with them falling off over bumps or putting them back in place, these issues are resolved buy how tight you mount the holders.
What I did not like is the bottle itself, its hard to squeeze and not much water comes out compared to my camelbak podium bottle.
^^^ This is my experience.
Increasing bottle security (over bumps etc) does make it harder to get on and off by hand - tightening the bolts down more or less changes the compression of the "knobs" and therefore how tightly the bottle is held. It is slightly more difficult to put the bottle back onto the frame (although I've been using the normal system with cages for ~25yrs and the cageless system for only 6 months).
The bottles are indeed harder to squeeze in my experience and the water comes out slowly, which I find annoying.
I run one on my CX bike which is sometimes used for commuting. With the Fabric bottle/system, I can commute with a bottle, warm up for races with a bottle and then ditch it for the race and since there is no cage on the frame, carrying the bike is not a problem. For this purpose, I'm happy with them. I would not put them on my everyday bike or a race bike.