The SanDisk Extreme Class 10 SD Card is pretty much as professional as it gets in terms of memory cards. This card is made specifically with DSLR users in mind which includes those that own the Canon EOS 70D. I actually purchased the 32GB model a year or so back and just now decided to pick up the 64GB model and use the 32GB as a back up.
The performance on this SD Card is miles ahead of the competition and certainly can’t be beat. The difference between transferring data from my DSLR to my MacBook Pro with the SanDisk Extreme Card compared to some cheapo card is mind boggling. If you aren’t using this card or haven’t tried one out yet, then you’re definitely missing out. And just so you know that it’s not only me that loves this card, then you can check out some other people’s reviews here.
This is probably the best SD Card for the Canon 70D out there.