SLX and XT both have ceramic pistons, Freestroke adjustment and tool free reach adjust.
Deore don’t have the ceramic pistons, neither do they have Freestroke adjust, lever reach is adjusted by allen key, so not tool free.
If it where my money I’d spend it on SLX.
Not sure about reliability, there have been a few threads relating to leaking banjos on XT
Problem with Shimano is you can’t get spares although they do come with a two year warranty, Hope are fully rebuildable but expensive compared to Shimano.