I too am surprised that you did not like the UA-1EX and suspect, like Steve suggested, that you may have had a duff one.
Originally I ran mine in 16-bit mode as I had it in its standard mode using the default windows drivers. Latterly (at the request of Gale Andrews who wanted me to do some testing) I downloaded the latest Edirol drivers and set the device into its Advanced mode. In this mode my understanding is that it runs at 24-bit rather than 16-bit. I record into Audacity with Audacity set at 32-bit floating to get the best headroom for editing as Koz suggests - and set at 44.1kHz. On Export I get Audacity to downsample to 44.1kHz 16-bit PCM stereo WAV files, using triangular dithering.
The results I have got with this have been very good indeed. I listen on a Rega Planet CD deck, feeding a QUAD 33/303 pre/power amp and on to QUAD ELS-57 electrostatic speakes which are famed for having a very detailed sound.
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BTW I would recommend looking at Brian Davies excellent ClickRepair software. It costs a little ($40) but its results are just a little shy of magical IMHO - see this sticky thread: https://forum.audacityteam.org/t/click-pop-removal-clickrepair-software/1933/1
WC