here's one thing to consider, though. the analog outputs of the ua5 are not pass-through. that is, the signal will still go through the the A/D converter, and then through the D/A converter to the analog outputs.
so, if you give an analog patch out of the ua-5 or the jb3, either way, the signal will pass through the ua-5 A/D stage. then it's just a question of how the D/A converter on the ua-5 compares to the D/A on the jb3. just a guess, but I'd think the UA-5 is still better. just something to think about.