To be honest I don't like the way it feels when it's down. Back in the day of DH on your cross country bike, yeah we'd put the seat down, but I'd only go down a bit like an inch or so, and more and it would feel wrong. Same still, If it would only go down a bit, it'd be great, but trying to get it into a spot that isn't too low or not low enough, it just feel wonky and distracting.
For most of my riding (the trails I do all the time) don't need one, it doesn't seem to make me any faster (or slower) its just a distraction. But for trails that are at or above my comfort zone, then yeah totally useful
The benefit of a dropped saddle is 2-fold
1) It allows you to let the bike move around a lot more over rough downhills, do it right and you can carry quite a bit more speed.
2) On really steep descents it makes getting weight back far less problematic. Dropping over the back of a full height saddle so ones chest is over it is difficult and can cause some scary situations.
I used to manually drop my saddle for some long rough descents and did wonder why nobody made an automatically dropping post. As soon as I found out about the gravity dropper I got one and didn't regret it
I think we all now the benefits as they are quite obvious. I just find personally having it low(while giving those benefits) feels very weird to the point of disconcerting. Not saying it doesn't help, just saying how it feels to me.
Tried a cheap o Raleigh rep one over a year ago and whilst it's not as solid as the elite I'm still using it , thinking about another for the Kona , both 27.2, had to do a bit of fettling (thick oil instead of grease and Spring tension tightened ) but it's still going strong after 1/1/2 years abuse , cable it comes with is too short but no big issue and it cost me about £80 new
T mars are different Ped , sorrento or something is the co that makes em , wen't for the RSP from evans so I could take it back if it collapsed second time out but it's still going strong .