I've got a WOW with the giant dressage blocks & I love it & so does my horse. It does dep on the fitter, but properly fitted it gives a v balanced position & is great for (human) bad backs.
I would ride on it for a while - the first time I tried one, it was like sitting on a spacehopper (!) & I would have got straight back off again, but cos I was doing a lesson I had to stick it out. Got used to it after about 1/2 hour. (It was spacehoppery cos it had too much air in it for my weight.)
Been there, done it and got the tee shirt. Saddles OK if you can find a good fitter but they are few and far between and I found they need adjusting more often than traditional flock saddles. My experience with owner of company was not pleasant and I ended up complaining to Master Saddlers
Got an Albion now and very happy with it and the saddler I bought it from - very professional