I don't have the webspace to put up reviews but this is my experience of pixlet on a 12" 867Mhz G4 Powerbook.
It's the same quality as DV only with a slightly smaller filesize.
I rendered the same test animation out twice. Once with pixlet and again with DV. 720x576 PAL resolution, no sounds. The clip has a duration of 16 seconds. You get the idea.
Pixlet's file weighs in at 46Mb and took about 5 minutes to render out of FCP 4.
DV took almost exactly the same time, looks the same and is 55.9Mb in size.
Unless there's some multi-generation advantage to using pixlet (which I haven't experimented with yet), the small reduction in file size isn't worth it.