For 2007 UD Masterpieces, I bought mostly retail from Target, and only when it was in the $1.59 Powerpacks box. It took me quite a while to collect all 90, and only with the help of my fellow collectors.
This year, I have purchased two boxes of 2008 UD Masterpieces, and I'm happy to report that I have collected 87 of the 90 base cards, and 11 of the 30 short prints. In addition, I've managed to get two autographs (one a patch-auto), two relics, two numbered framed parallels, two red parallels, and eight black parallels. Not bad at all. I only had one double after the first box, and now I have 21 after the second box, but that can be forgiven for the nice collation out of the two boxes.
The prime cards of the second box, besides a Brandon Phillips Strokes of Genius (my second Phillips auto from this set!) auto and a Jered Weaver relic, are the following two parallels:
The Chipper is really nice, and the Oswalt is numbered 036/100.
All in all, I'd say that the 2008 UD Masterpieces are very nicely done, save for some factual errors, well collated, and a pretty good value for what you get in a box.