I've been using the M8 as my primary camera for 2+ years now, my DSLR back-up has been in the hands of my teenage daughter during this time (yes, w/ frequent inspections ;-)). Occasionally I switch over to a NEX-5 with ltm-M adapter, since I can flip up the viewing screen and use it like a TLR (sans reversed image), but otherwise I've had a much better experience with the M8 than any other I've shot with over the years - warts and all.
WRT the Fuji XP1, if it had an articulated screen, I'd be sorely tempted especially with the M adapter on the horizon. The NEX has it's own share of issues and replacing it is a more likely scenario for me.
Good luck with your M8.