JackHoffmanIn all honesty, I'd be very surprised to actually "hear" the result of jitter. There are plenty of non-asynchronous DACs (and DACs labelled as asynchronous that aren't actually asynchronous). There are detailed threads on headfi and around the web, including ones where people solicited recordings of jitter (I never found a recording demonstrating jitter).
I would love to hear jitter myself and then I would happily only purchase fully implemented asynchronous DACs, but so far I see no reason to upgrade my T1 to the new version. Also, a lot of people confuse buffering issues with jitter... buffering can be a pain in the ass which is easily resolved by software settings and/or USB port troubleshooting. "Stuttering/stumbling" are the two most identifiable buffer related issues, which have nothing to do with jitter, and everything to do with buffering.
Anyway, just some thoughts on jitter. It's a hotly debated topic, much like ASIO vs WASAPI.
Recommended reading:
http://www.head-fi.org/t/198245/noob-alert-what-does-jitter-sound-like/
http://www.head-fi.org/t/546092/confirming-whether-your-dac-is-asynchronous-as-claimed-or-not
http://www.positive-feedback.com/Issue43/jitter.htm