I wanted to point out something as well to help with the people that use CMSS-3D and Dolby Headphone so that it might help to understand what might work better for you. Dolby's is aimed at simulating a surround sound setup and offering correct placement according to a properly setup one (which is why it also elevates bass levels to give a psuedo LFE). Creative's on the other hand is aimed at recreating the space that its emulating so as to give you the feel of being in that space (so in gaming its trying to give you the feedback that you'd get in the game world). I think some people go in expecting different things from tech like HRTF. Some expect head-tracking like what Beyer's focus was. Likewise with the Smyth system which is trying to achieves something else as well. Anyway, I think it helps to understand what the tech you're using is going for so that you can maybe choose one that better fits what you're wanting or so that you can maybe better appreciate what its doing. Sorry if this was already pointed out before.
In all fairness the title doesn't say Dolby Headphone experiences only, it just says particularly with Dolby Headphone, which I think gives some the impression that's not default, so I do think you reiterating that is beneficial.
I wish there was a company that would offer something similar to the Mixamp but with DTS Surround Sensation, as I seem to generally prefer DTS' implementation of similar tech over Dolby's.
Definitely that is the biggest concern here, but I think it would be possible to be disappointed with the AD700s from a technical standpoint. Of course as far as gaming, using them in stereo definitely would expose its deficiencies more.