I've got a couple of class 10 sd transcend and have had no problem. I've used transcends CF with my Oly E1, E3 and E410 and really find them quite dependable and fast. Don't let the low price scare you; get them from a reliable seller and enjoy them.
I have couple of them a 8gb and 16gb class 10. I did a now scientific test when I got my first one, I ran off 18 shoots on my t1i with a delkin class 6 and 24 shots with the transcend class 10 in burst mode before buffer lag. So it does write a bit faster then class 6.