I had the same experience when I first received my HD-A1. My (additional
) explanation was this: current TV sets and projectors already had a better horizontal resolution than present in SD DVD and NTSC (or PAL) images. So when you feed it a much better picture, resolution-wise, it will already show it.
BTW, that's why I always advised people who weren't able to buy a HD player and a HDTV right away, to start with the player. They could benefit immediately (be it in a limited way).
The HDTV makes more sense if you really are into HDTV channels or own a HDM player (which now should be: a Blu-ray player!).
Cees