Truthfully, the experience between the cameras will be more similar than different.
The 70D has a more advanced live view system, especially with the right lenses. So you will get faster and smoother AF in live view, especially in video. The 70D also has a touch screen, that some people like.
The D7100 has higher image quality, but that's primarily when measured in a lab. If you are using kit lenses, printing 4X6 images, posting on facebook, you may never notice the difference in image quality. But if you are pushing the limits more often, the D7100 will have better dynamic range and less noise. Taking a regular jpg shot in good day light, you won't see any difference. But in low light, or if you are lifting shadows in RAW, you benefit with the Nikon. (I shoot with the Nikon D750 which has fantastic dynamic range. I'm blown away by my ability to lift shadows in post processing).
The Nikon has a 100% viewfinder -- you can see the whole image you are photographing. The 70D is only 98%, meaning you get a bit more on the margins that you don't see in the viewfinder. The Nikon has more autofocus points and may get slightly better autofocus when using the viewfinder. The Nikon has dual card slots. Nikon also has a 1.5 crop factor while Canon uses a 1.6, meaning most of your lenses will be a little wider on Nikon, which is beneficial for landscapes.
The biggest question is the lenses. Though for the most part, they have overlapping lenses... you may find that one brand might have a more specific lens you wanted, or at a better price. For example, Nikon has a fantastic high quality stabilized low weight 300/4. It's a unique lens, and nobody else has anything exactly like it right now. Or you might see that the lenses you want are a bit cheaper in the Canon camp, etc.
They are both mid level/upper level APS-C cameras, they both would serve any shooter well. There really is nothing you can do with one of them, that you wouldn't be able to do with the other. To some extent, you might just want to see which fits better in your hand.