Why haven’t you upgraded to Di2 / electronic shifting for MTB?
It violates my appreciation for simplicity. Electronic shifting adds needless complexity (and cost) to a simple system that is easy to maintain and set-up with diminishing returns as no reviews have called it a “must have”. In my personal experience I have demoed (road) bikes with both Dura Ace and Ultegra Di2 as well as a spin on a XTR Di2 mountain bike. Yes, they worked, but all of them were unimpressive. Maybe a better way to say it is that they were uninspiring. It’s more junk on a bike I don’t wish to look at or play with. The feel is still very Shimano; some call it smooth. I say it’s vague.
On that note, I am an unrepentant SRAM fan. Yeah, their brakes too, but that’s for another discussion. I prefer the feel of SRAM shifting…period. Their tell-tale “clunk” upon shifting is ubiquitous throughout their line. I’m not saying it’s better; rather I simply prefer it (but, it’s better…h8 on).
Finally, I firmly believe that SRAM won the shifting/gear wars hands down with the introduction of 1X drivetrains a half a dozen years ago. Now with the GX Eagle they have put the proverbial final nail in the coffin of the front derailleur for mountain bikes with Eagle’s efficacy at an attainable price.
My reason is very simple: Mountain Biking breaks things, breaking expensive things makes no sense. If you would choose that system, you are one kicked up stick away from an expensive disaster. I don’t even care if it does work well, it would detract from the fun if it was something you had worry about.