I am LOVING the always-on Canon EOS 70D viewfinder level indicator. This feature marks a great step forward in resolution of my HLDS (Horizon Level Deficiency Syndrome).
Some of the other recent Canon DSLR Cameras have a viewfinder level indicator that utilizes existing focus points or the exposure scale at the bottom of the viewfinder to show the camera's state of levelness. This feature has been extremely useful to me.
But, as soon as I half-press the shutter release, the level indication goes away. I am relied upon to maintain the camera's levelness as I focus, adjust framing and then shoot. To compensate, I often focus, switch to manual focus mode, frame, turn on the level indicator and then take the shot. I of course need to remember to turn AF back on before shooting the next scene.
I maintain a Canon wish list (it might show up again as a "What I Want from Canon for Christmas" post). Having a viewfinder level indicator that continues to function up until the shutter release has been on my list.
With it's always-on (when metering is live), easy-to-see, dedicated, superimposed viewfinder level indicator, the EOS 70D solves that problem. It is even available during AI Servo full frame rate burst shooting (if I can maintain the brain power to use it). While this feature seems minor and insignificant, the small improvement can make a difference in the quality of your images if pixel-level-destructive image rotation is no longer required during post processing. Having properly-leveled images right out of the camera can also save many hours of work after a big shoot.
Now, Canon, would it be too much to ask to have the viewfinder level in the previous so-equipped DSLRs remain live until shutter release via a firmware update? My EOS 5D Mark III bodies especially need it!
And while I'm asking. For the times when I still don't get the camera level ... Since the camera knows the level reading at the time the shot was captured, record the level meter reading in EXIF and then give me an option to auto-level the image in DPP (Canon's Digital Photo Pro software).