Right, It's surround sound, but it's not actually 7.1 audio. It's an imitation of it.
Basically go with the DT 770s. They should have much better sound quality, and there should be some options in windows to enable surround sound on them if you choose to do so. Even if you don't enable any enhancements they should still be able to produce sound accurately and you can't go wrong with them.
In short you will be able to hear footsteps behind you without a problem on the DT 770s, but the 770s will also make for a great pair of headphones to listen to music too as well.