I've been trying the 0.9.x releases for months on my admittedly slow old Athlon on my main PC. Never used it on my HTPC. The performance has consistently been terribly, whereas 0.8 was blazing fast -- so I kept going back to 0.8.6. Even at vers 0.9.9 it was bad. Its a little ridiculous that 0.8.6 could play SD MPEG-4 ASP at less than 10% CPU, and h.264 at around 20%, while the 0.9.x releases take forever to load, hog 35%+ CPU playing an old DivX, and can't even start the video smoothly, displaying distorted colors and picture for several seconds and occasionally just choking on videos.
Then I downloaded 1.0.0 and it runs really well, almost as fast as 0.8.x with no real issues. Go figure.