Well I received my fixed seat post the other day with 25mm of setback. I have 2 XC rides on it so far, 30 miles. It has made the bike very rideable without a dropper, with the dropper extended at correct pedaling height, if not dropped even on very small rough areas the seat would be interfering big time. With the fixed post I have the seat all the way back to the max mark on the rails. The bike is more comfortable while seated, I am 6ft tall but have rather longer legs I think than arms and torso so with the dropper at 0mm setback and the 75* seat angle I found on grades I would be pushing myself way towards the rear of the seat and would have more but ran out of seat. That urge is gone. Riding most of what I ride I can get by like this for now. The biggest drawback is in flat corners I can't lean the bike nearly as well as the seat will still interfere at a certain point. I think I am going to get a few more rides in to see overall what I think. I see PNW has a lifetime warranty on there droppers so I may end up going with one of there 150mm droppers but I will see. As of now I am ok with the fixed post, I got one trail I need to ride that has a lot more steep technical drops that I want to see how it feels there. I do like the fact I have a fixed post that can't really cause me a problem.
Also it might have been in my head but with this seating postion being more "slack" I seemed to have more power when grinding up a grade when seated, that may not be so. I felt good today when i did the 2nd 20 mile ride so I can't say for sure at this point if that contributed to more power or not. But with me being SS I am up out of the saddle on any decent climbs anyhow so I am not taking advantage of a steeper seat angle there anyhow.