I'm using a 2Gb Transcend card in my e61 and it hasn't given me any problems at all. I really can't comment on the speed of it, because I have nothing to compare it to.
As for a case, I'm using a case from Best Buy made for the Moto Q that works, but I'll be getting this Krusell case very soon! I really like Krusell, and I've been looking for a case that has storage for extra SD cards. I had a similar case for my 8125 and really liked it!