It’s funny @Guilherme how you jump on every treeless thread and repeat ad nauseum that the physics of treeless saddles make them bad. But… if I recall correctly you’ve never ridden in them and you never answer when people ask you about the continued success of riders who use them. And by success, I don’t mean necessarily winning- I mean a horse that continues on a lengthy, sound career. Am I a big proponent of treeless? Yes and no- I am a big proponent of whatever works for you and your horse. One of my horses goes solely in treeless (with the blessing of him, me, vet and massage person), one is perfectly happy either in her treeless or in her treed, one cannot go in treeless. If treeless works well for someone, how is that skin off your nose? And BTW I have used a Port Lewis Impression Pad to check fit and it shows the saddles as balanced with no pressure spots but prehaps the pad doesn’t understand physics…
Yeah, I have a “thing” about them as I don’t consider them safe for the horse. So sue me!!! 
And you do recall incorrectly. I’ve tried the Bob Marshall and an earlier model Ansur. Found both SEVERELY lacking in the load distributing department.
If you can advocate, so can I. What more is there to say?
G.
I apologize about thinking you had not tried one.
The idea that they are not safe is pretty hilarious though
I own a torsion treeless saddle that I use for endurance, and know several other endurance riders who ride in treeless. A BIG factor in treeless is an appropriate pad with high density foam and provides spinal clearance. I personally use a skito pad.
Endurance horses travelling 50 or 100 miles in a treeless would not pass the vet or not be able to do multiday rides (and pass the vet in and vet out) if they were causing problems.
My treeless has proven stable enough for mounting from the ground on a few different horses, but not overly round/no wither types. I have had zero issues with fitting it or it moving around.
I would not recommend it for a heavyweight rider, nor without a good, high density pad. The pad is as important as the saddle.
I should add I’m not against treed saddles; I have a treed dressage and jump saddle I like too 
