Go to a service station that fills up big trucks; the fuel doesn't stay long, so it gets winterized properly. The only gelling instance I had was filling at a lightly used Shell station; once I got it fired up I dumped a bunch of PS in and never had an issue again (I also went to a different station from then on).
There's two kinds of Powerservice, BTW: grey for summer (just cetane boost) and white for winter (cetane and anti-gell). I used it religously for the first year or two, then stopped. No issues in 259kmiles, other than the one gelling issue.
I also stick to just Irving's, and try to avoid other places. Cheap fuel can be not so cheap in the long run. The Irving's I go to have the truck pumps, and so they get lots of turnover also.