My impressions are the UPAC regulators are OK out of the box. A bit softer metal than original or Vintiques and as Neal noted not as smooth. Vintique's have a wrong type rivet holding the arms to the gears which causes binding, fixing that they work just fine. (pm me for more details if needed).
Also beware that there are (at least) three versions of regulators in the wild. Early (type one) needs different mount holes and bottom glass channel than type 2 or type 3. DavidG has notes on the three styles in his errata web page on the Early V8 Club site.