Wipeout HD Preview version from March 2008 has a few interesting differencies compared to the final version. Different sound effects, different camera angles after race finish and really buggy AI ships are 3 examples. In this version only 4 tracks are playable:
Vineta K
Anulpha Pass
Moa Therma
Chenghou Project

I just discovered yesterday when I was leaving the controller on the table being on the main menu screen that the preview has an autoplay mode just as the final version has. In this autorun mode all 8 tracks are shown in a random order. I have not seen any differencies in track graphics or lightning effects on the 4 playable tracks compared to the final version but when I got to see autoruns on Metropia and Sebenco Climb there were a few obvious surprises:

A lot darker than the final version! Much more like the Pulse version. The final banked corner is almost completely in the shadow. Looked pretty cool, like Metropia being a little more like Gotham City.

Sebenco Climb
Here, only a part of the track differs and that is the cave area in the end of the lap. It is a lot brighter. Clearly white inside instead of just dark like the final version. I liked this version more.

I guess photos are wanted but it is kind of difficult to take pictures since angles change pretty rapidly. I don't have any recording equipment unfortunately.
I guess I could try taking a few photos later on. My debug unit has YLODed twice but I did a reflow yesterday so hopefully it will live for a while now.