I had a U-Retro in a parts bass with Duncan Bassline p'ups. I don't care for Basslines, but the U-Retro made them sound decent. Not decent enough to keep, but that wasn't the U-Retro's fault.
Pre's are so dependent on personal preference (what works for me, might not work for you...)
I prefer Barts and Aggie OBP1 Pre's. Simpler is better, the less knobs the better; and, ya know, there's that 'old and cranky' thing goin' on.
Would love to try the Audere Pre, tho...