I've owned the Spacedeck for about one year and have two arms mounted (see system). Rjones gives a pretty good description in his discussion of the Interpsace and the Spacedeck is even more of the same. One thing I find with the Spacedeck is how the lower, middle, and upper ranges of music are CONNECTED and SMOOTH, no weak link. The Spacedeck has such an ANALOGUE sound while voices, strings, details are extremely well defined. Not technical descriptions, I guess, but accurate to my ear! :-)
It is true that a SD will smoke the P25, IMHO. I read a review once where the person said the SD made the P25 sound like a "nightstand alarm clock" by comparision. Not sure I'd go that far, but I compared many a TT before buying the SD and I did feel that one needs to go up to the TNT line of VPI before besting the SD, for instance.
Many folks use Dynavectors, and they are very nice with the 'Nots. Also, some opt for Graham or Moerch arms - mostly those who bought the SD with the original metal Spacearm (they are now carbon fiber, major improvment).
One caveat, given that the 'Not is a non-suspended table. Tom Fletcher of 'Not, who gives minimal documentation at best, suggests a "solid wood base" for support. This will work, but give it a wall-mount and the table will absolutely double in performance. I use a DIY wall-mount with a 3" piece of rock maple as a base. A friend thinks my Spacedeck mounted in this way sounds as good as his Hyperspace.
Short story, if you buy a Spacedeck and you won't be sorry.
