I googled it and yeah. The HD has a 1280X720 screen resolution and is slightly larger than my old T-Mo S2 (with a 800x400 4.52 screen). The HD is for high definition as you stated.
And yes, I know for a fact (from listening) that the S2 is the best DAP I currently own. Even in the state it's in now, where the synergy/soundstage/3D/clarity is diminished in conjunction with my Shure SE535, it is still better than my other DAPs. It was better by leaps & bounds, now it's just better.