Splurged and got the new Star Trek - The Original Series on HD DVD day before yesterday and watched the extras and the two part episode The Menagerie yesterday.
First of all, although the title doesn't make it clear, these are the "remastered" episodes that have been on TV over the past year made from the original film negatives, with new special effects. I decided to get the HD DVD set becauise my local Fox station's broadcast quality is atrocious - the remastered episodes actually look much worse than the original episodes airing on other stations. I wasn't disappointed - the picture quality is stunning - as good as any other Blu-Ray or HD DVD I have, and it's startling to see how sharp and colorful the episodes are (it's also a major rush to watch the interactive exterior tour of the ship in my movie room on a 6' x 4' screen - you can really feel the size of the ship). I also changed my opinion on the special effects after watching it - while on Fox the new effects lack contrast and really do look CG, on the discs they look much, much more realistic, and blend with the original episodes far better than the originals would. Keep in mind that on top of the fact that the original effects were crude by modern standards to start with, the process that generated them meant that they were several generations removed from the original image, so if they were left in you'd be cutting between this razor-sharp image of the actors to a muddy, blurred, dated effect of a ship. The effects are now consistent with the original scene footage in picture quality.
One other thing I expected was absent, and that was flaws in the sets - while they aren't perfect, it's not immediately apparent that the sets are cardboard and plywood, as I expected. The sets actually look awfully good, and their relative blankness actually focuses more attention on the acting - which is really good. It's also bizarre seeing the actors in such clarity (and such size on a large screen) because you really feel like you're in the same room and meeting these people for the first time. Really weiord feeling for a 40 year old series!
Bottom line for me is that I think this is a really good reworking of the original series to bring it up to current standards across the board, and let you focus on the artistic merits of each episode, as opposed to the shortcomings caused by budget and technological constraints. I'm lookinf forward to watching more in the coming weeks.