I have an Adata 16 gig class 10 SD card that eventually went bad on me. They are supposed to have a lifetime warranty so I'll see if I try that.
That microsd gave tons of headaches. My Droid 2 would start acting funny once it went bad. It would freeze, pics would show up sometimes and sometimes now. Lots of forcecloses and my computer would read and read it. I pretty much had to reformat it to get it working again but a few days later the problems would pop up.
I went ahead and bought a samsung 32 gig class 10 once I got my Amaze. So far so good this thing is even supposed to be water proof with a 5 year warranty. It was around $37 from Fry's.