I've been running EX1 for a few weeks. Just getting it was a challenge as SRAM aren't bringing it in to Australia at the moment. Combine that with Sram geo-blocking it's sale every where else online... a very frustrating experience. I eventually found an online bike store in Spain willing to ship it to me.
First impressions are not anything exciting. I don't find the shifting much crisper than the standard Shimano XT 11 speed I was running... still get the occasional gear crunch. The spread of ratios is certainly bigger with 1 or 2 shifts feeling a little too big... but not too much of an issue with the ebike's torque. I'm hoping it's main advantage will be durability and chain strength.
I'm not sure if it's related, but since installing the EX1 system, I've had an annoying creak somewhere in my drive train. I suspect it has something to do with chainline or derailleur tuning... but not 100% sure. Adjusting derailleur cable tension (at the shifter) seems to fluctuate it's severity but I can't get rid of it completely.