I'm looking at the salsa Timberjack - they now offer a 12 speed sram nx eagle for 2019 - the next next in line, and a few hundred $ less, is the slx 11 speed - I have 2 ??
is there much difference in performance / climbing ?

and my main concern is chain reliability ?  the 11 speed chain is already getting thin and the 12 speed has to be a little more thin - would that lead to a greater chance of wear or breaking?
thanks