Installed a 11-42 MX3 this weekend, seems to shift like my old 11-36.Not ridden it yet tho but it seems ok to me. Only issue is in the lowets gear it will drop down the cassette when you do a full revolution of the cranks, not that I will ever do that when riding.
Using it with a medium SLX mech, b screw wound nearly all the way in and a 36t chainring and KMCx10-SL chain. Out of the box the chain was the right lenth, 114 links, which was nice.
I did shift my BB spacer to the NDS to give a better chainline when in the lowest gear, i’ve been bending mechs outwards so im hoping this will help too.