Small update: decided that the powerful bass of the ep-630 was really more of a flaw than a virtue up against the vibe/t25 relatively flat response. So I gave away my ep-630 to a needy officemate. Ultimately it wasn't the superior sound quality or appearance that most convinced me, though, it was the realization that I didn't have to live with the awful cable noise of the creatives.
So, it seems to me ever more likely that the t25 are coming out of the same factory as the vibes, now that I've got used to their more realistic bass response to give them the full thumbs up. Certainly these are not cheap knock-offs, as the sound quality is really quite good, better than the ep-630 and Shure E3 which are the only other IEM's I've tried.
This brings me back to wondering what the OEM status of these headphones is, though. I was always self-righteously pleased about getting the OEM ep-630/cx300-- why should we pay double just for the privilege of badge-engineering from a snooty brand, when we could just buy from a wholesaler going to the original manufacturer? But the question is who owns the design-- in the case of the creative/sharp/senn/AKG headphones, obviously the design was from whoever licensed it to and manufactured it for all of them. With the Vibe/t25, it's not so clear. Either V-Moda is seriously overselling its role in the engineering process, or somebody on the production end decided to rip them off. The rumors of legal proceedings make me suspect the latter, which makes me wish I had just shelled out for the actual product. But we don't really know yet what the real answer is.
FV