Well, after about 1.5 weeks & ~45 hours, my Z7's are working out very well for me. On other wide/big-bore IEMs, I have really liked the stock Sony hybrid ear tips (large/light blue). However, on the Z7, not so much. Luckily, I found a pair of the now out-of-production Phonak gray silicone tips in an old IEM case, and these work terrifically.
I do experience audible distortion at higher volumes, but pretty much never listen at those volumes. Bass has settled in nicely, and w/ the Phonak tips, it is very well controlled (could sound a bit flabby w/ the Sony tips). I enjoy the out-of-head sound stage, and I have zero issues with fit. I was planning to pony-up for the Earsonics Velvet, but after reading about their build issues (yet again...why do they always seem to have these issues?) and my good experiences w/ the Z7, I think I'll stay put for now.