I fitted a full GX drivetrain to one of my bikes about 3 weeks ago. I’ve done a few rides on it now and cannot tell the difference between it, and the X01/XX1 mix that’s on my garage queen bike – I’ve been very impressed with the GX stuff. I ride Shimano and SRAM 2×10’s as well, so not really in any particular brand camp. I fancied trying the XT 11 speed with 11-42 but found out the cassette weighs about 50g more than the GX cassette. If you’ve already got an XD driver for your wheel, I’d definately recommend the GX stuff.
Oh, FWIW, I haven’t noticed the SRAM mechs deteriorating any faster than XT/SLX stuff over time – but then I have bike cleaning OCD 😉
p.s. I got my GX kit from Springs and Things and Hibike, who were very competitive on pricing.