The beds and rooms at DTS are a little nicer, and if you're getting a suite there, then I believe you get queen beds, and not doubles. The room is smaller than Embassy Suites. BUT, no breakfast. I've stayed at both, and we always end up back at Embassy Suites, or even Homewood Suites, down a little further on Harbor- all are HHonors members.
The transportation to and from Embassy Suites seems better to me- we've driven to the Mickey and Frieds lot and taken ART- getting in and out of DTS is a little harder than in and out of Embassy. We last stayed at Embassy in December and as always had a great experience. Can't beat the cooked to order breakfast!
In fact I have a reward stay at Embassy Suites next weekend.