I can't comment on the shift quality, but will advise being careful when downshifting on the front under load. I had converted some of my 3x bikes from 8-speed to 9-speed in the back (with 9-speed chain) without touching the front derailleur or crankset. Shift quality was fine -- I was able to move up and down the crankset as I was able to before, but I could somewhat regularly induce "chain suck" when downshifting under a moderate load (like downshifting to the low ring while pedaling in advance of a hill). I don't know for sure, but it seems like the slightly narrower 9-speed chain wasn't able to free itself from the 8-speed chain rings, and I'd suck the chain right up into the bottom side of the chain stay sometimes. I couldn't say WHY I had this problem. Some seem to think the ring spacing and/or thickness can be a factor while others say it's not. I do know that the chain suck problems went away when I went back to 8-speed on the back with an 8-speed chain.