I figure I'll give a few impressions of the 1964-T since I have had them for a week. For what it is worth, these are my first customs, and I currently own the DBA and recently sold my TF10. I listend via uDac, Sansa clip+, Sony A818, Sony E345, Cowon U2.
The fit came out very good. I have only lost my seal while eating, but I have not run with them yet (not sure that I will). I have even found the comfort to be better then any universal I have ever owned, and I typically use foam. The quality is very good other then the "glue issue" I posted about on the previous page. Although it isn't a structural issue, I am fairly disappointed at the look. The cable is fantastic. The pelican case is much nicer then you would think.
When I first put these in and played them out of my uDac my heart sank, but not in a good way. There was no AHA! moment like I had with the DBA. My first thoughts were "Crap I just spent $350 on customs that I don't think are better then my universals". After several days of listening and some direct A/Bing I have come to love the 1964-T though. It has a fullness of note that the DBA is ever so slightly lacking. The DBA has more air, but the trade off is a thinner note. This is most noticeable in the lower mids, making male vocals sound more authoritative. The 1964-T still has the clarity and detail of the DBA, but the highs are slightly less sparkly and aggressive. IMHO it sounds more natural and accurate. It makes the DBA seem a little too aggressive. I don't find the 1964-T "laid back", but simply smoother. I can listen for HOURS and do not find it fatiguing in the least. The sound stage is very good in my opinion. I find it to be the right "average size"; not expansive, but not overly intimate. I feel the separation is very good, but maybe a hair behind the DBA due to it's airiness.
Comparing to the TF10, I find the 1964-T to be everything I wanted the TF10 to be. The mid-bass hump is gone, and the mids are no longer recessed. Plus the comfort is worlds apart. The TF10 had more sparkle from what I remember. I always found the TF10 highs to be very refined though.
In summary, if you own any high end IEMs, do not expect to be blown away out of the gate by the 1964-T. It instead takes a little time to realize that it does almost everything very well. Although I found other IEMs in that category boring, the 1964-T still seems to stay very musical. It is the first time I have owned an IEM where I feel that my sources / amps are now the weakest link in my chain.