I think it's also sold.
this was the chronology, as I remember it. I think 27.5 became a thing with the rise of Enduro as a sport. it was a way to keep the long travel and mythically better "flickability" of 26" but get some of the benefit of bigger wheels. then they came up with 27.5plus, which was trying to make a 27.5er into a 29er by putting balloon tires on it.
meanwhile, 29er geo has been making room for longer and longer travel, to the point now where it can compete with the little wheels.
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and I would agree with Braf on the components, esp for newer riders. It's hard to look back on those days and remember anything but the times I had problems with it. I've also learned over the years that that the real problem may be somewhere else; such as a bent der hanger, gunked up cable housings, etc.
all that being said, I did briefly have a GX rear der. first gen from when they rebranded everything away from the X.x series. the B adjust had this janky-ass rubber grommet holding it in the der frame that would get out of alignment. never realized how important that screw was until then. before ultimately replacing the whole thing with a ebay closeout find on an X.9, I found a bigger screw (a coarse-thread sheetmetal screw, iirc), removed the grommet and force-threaded it in there. I also dremel'd a notch on the B-adjust plate to make sure it didn't slip out again.
but that was a long time ago. hopefully, they're done with that shit.