Brad, in my notebook, I wrote that on 8/24/14, Sam rated Versatex best, then Azek is almost as good. Kleer is nowhere near as good. Celuka/Koma have a good hard exterior, but the interior is grainy. He noted Versatex has application videos that are helpful.

On 1/28/15, Brady said he likes Palram, then Komatex, Sintra then Ex-Cel. (He said Excel used to be bad, but is now very good.)

I personally don't know any of these brands, but since I had written this down (as I do have an upcoming need for PVC), I thought I would share this past information in answer to your question.

Chuck