Bought this camera over 2 years ago and been using it constantly ever since. It fits very well for the enthusiast/advanced amateur as I classify myself.
What speaks for this camera the most is it's versatility. It has a lot of features and then some;
WIFI - Which I love using for posting pics on Instagram or emailing someone the pic the immediately instead of waiting to get home.
Touchscreen - At first, you think it's a gimmick, but I was surprised on how much I actually use it. Especially when zooming in picture (same technique as on a smartphone/ipad etc) so see if it's properly in focus or if it's blurry due camera shake, etc.
Articular screen. Very useful, not only for filming but also for when you want to shot @ a low, high or any other unorthodox angles. At this point it feels like it would be difficult for me to change to a new camera that doesn't have a articular screen or at least a flipout screen
AF microadjustment - Was missing on the 60D, but is back in this model
And there's other stuff like in-camera-HDR, etc.
But the biggest selling point and upgrade from the 60D is the the AF, bot the optical and the live view AF. The 70D is faster and has more AF-points and crosspoints and shots 7fps which makes it a joy to shot action shots. I used this camera a lot for taking pics of my 2 ½ year old kid running and jumping around and it keeps up great.
With the new live view focus (which comes most in hand when filming) it's now actually useful when taking pics. When taking landscape pics and using tripods I love using the live view, and also as mentioned before when shooting "@ a low, high or any other unorthodox angle".
IQ: Good but relatively speaking not that impressive as it basically has the same IQ as the 4 year older 7D and 3 year older 60D and also the more amateur oriented and cheaper 3 digits series such as 700D, 650D & 600D. Just a tad cleaner images at high ISO. But still, you will get great images from the sensor, especially if you have good glas on ofcourse. But if you come from a one of the other cameras as mentioned and expect a big upgrade in ISO performance, you will get disappointing.
You can get useful shots at higher ISO if you expouse correctly, for example
This shot is @ISO 8000. I usually don't get these clean shots at that high ISO though.
Some more samples
Here I had the camere on a rail or tripod (don't remember). The articular screen made this shot so much more convient as I didn't have to squat down.