having moved from a 60d to a 6d, i would personally recommend to go 70d
i can never go back to 60d lol, unless shooting in broad day light
on the 70d you'd get a brand new dual pixel sensor, digic 5+ processor (as opposed to digic 4), 7 fps photo burst mode, better high ISO, video auto-focus, wifi (pretty useful for having clients view and rate pictures on a tablet after a shoot) etc
i would say goo for 70d, 60d raw you're not getting much resolution anyways (less than hd), no matter what sd card you buy.
70d specs say that its compatible with uhs-i cards, so im assuming its probably the same sd controller as the 6d, not the slower one of the 60d/rebel series, which would theoretically mean faster write speed for raw.
and according to canon website, yes 70d is capable of hdmi playback/monitoring like on the 60d:
Video Out Terminal
HDMI Type C (Switches automatically to suit the resolution)
Video output: 1080/60i, 1080/50i, 480/60p, 576/50p
*Switches automatically to 1, 2, 3, or 4 to suit the TV
http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_70d#Specifications