Disneyland's lead up from the stretch room to the loading platform add a lot of suspense to a rather tame ride. I have to give the nod to Disneyland's version.
(Although I go to Disneyland frequently, my one visit to the Magic Kingdom in 1997 was only a half-day, and we only had time to rush around the park and go on about five rides.)
WDW's version just comes off as a better paced, more thought out version.
The WDW version lost a few points this past year though. The new additions (the interactive queue and the CGI hitchhiking ghosts) SUCK, in my opinion. They're too kiddie-oriented and don't match the style of the rest of the attraction.
Ive only been on MKs HM, but it seems much superior then DLs. Now for Buzz, Magic Kingdom's seems more twords the movies, so thats getting my vote.