Anyone know anything about Promaster SDHC cards? My local camera store won't touch Sandisk or Transcend and only carries Promaster and Hoodman cards which they say are higher quality.

I was going to try a 16G class 10 ($99)

Plan to use in a Canopn T2i even more than my EX.

Can't speak for Promaster but I can for Hoodman... I have several, the largest being 32GB. I'm very pleased with them.

Never heard of Promaster !!!! There are many cards that have been tested and approved for use in adaptors, I would simply stick to one of them. I personally, have never had a problem with Transcend, both class 6 and some recentlly purchased class10. Been using Transcend in both my GY HM100 and EX1 for over a year, and more recently my newly aquired Canon 550D, never had a problem with either the old green belt or the newer red belt versions. I purchased the class 10 because they were only £2 more than class 6 for the 16bg card. As always, its a case of finding something that works for you, and sticking with it. But I certainly would not use an untested card, on the word of an individual shop. They probably dont know what an EX1/3 is, they are in business to make a profit, that normally means, buy low, sell high. Stick to the approved cards, and you wont go far wrong, they are all so cheap now.
Check this out Amazon.com: Transcend 16GB Class 10 SDHC Card (TS16GSDHC10): Electronics
You wont go far wrong. And less than half the price. As always, only buy from reputable dealers, there are a lot of fakes out there.