I don't really have all of the head-fi vernacular so here goes nothing.
I've changed the tips to get what I think is the best fit. I have had westone 3's, I still have my yamaha eph-100's, jvc fx101, velodyne vPulses, monoprices and I just don't get the feeling that these have much low end punch. Even with my EQ'ed htc one x as my music source I can't really seem to get these to really bump. These seem to be on the level of my ath ck6's. Maybe I got a bad pair. Such a shame since these are beautiful and incredibly well built.
I actually bought them because I remember reading your post about them and saw them at the apple store today. I'm going to give them the full 14 days and I'm curious to see if they get significantly better than my other options.
I'm sorry to hear about your experience so far with the C5. It could still be burn-in as I recall the bass improving over time. It could also be a bad pair or just our subjective listening experiences varying. For me, the best all-around bass I ever heard in a headphone (quality and quantity bass + sub bass) is a tie between the ATH-PRO700MK2 and the M-Audio Q40 (both circumaural). If those are a 10, I would give the C5 at least a 7.5 and feel that they are bassier than several of the headphones on the basshead list. I believe their frequency chart shows highly elevated bass. While I have not heard the V-Pulse, it would very likely have more bass and sub bass than the C5, but I don't know it would match the overall sound quality which has value to my ears as well. I have returned several headphones this year that didn't meet expectation and have come to realize that someone's ideal headphone is a unique and personal choice. I'm glad to hear you are able to return them if they are not for you.