My initial requirement was a little limited in scope, although with useage I now see other unforeseen applications.
I bought the UCA 222 to interface my keyboard/effects processor/mixer with my desktop PC to record my musical efforts. Having experimented with different operating systems, I found that it works happily on XP 32 bit, Windows 7 64 bit, and Vista 64 bit.
The software supplied, notably the free open source 'Audacity' program (with a big thank you to all the writers involved in its production) has given me real pleasure, as I record, edit and multi-track my Yamaha keyboard. The final production is invariably flattering to my skill level. The connections on the UCA 222 allow me to do this using the headphones output, so even at orchestral levels I don't have to annoy anyone.
For me, this inexpensive interface works really well, and has been a very worthwhile purchase. Oh, and good service by Blue Aran too. Thanks, guys.