I have used Sandisk cards for five years now and have not had a problem.
My manual .. in case you did not get a manual .. states the approved Sandisk cards are the Standard .. Ultra ll .. Extreme lll and llll. Anywhere from 1 to 8 GB.
I use the Extreme 8 GB 60 mb/ s card and the Extreme lll 4 and 8 GB 30 GB/sec cards and an Extreme llll card at 4 GB.
For all practical purposes I don't notice much difference. If you are not shooting RAW a couple of 4 or 8 GB cards or more if you want would serve well on a big trip. I don't like to put everything on one card and always carry extra cards and batteries.