I have been using XP folder compression on my laptop for over a year and a half, and on my desktop for just over a year. XP compression technology is worlds ahead of previous versions. I started using it on my laptop because the 20GB drive was filling up fast. It worked so well that I now use it on some folders of all my drives. As for the speed hit, at today's processor speeds, and at drive read speeds the delay is very small. When you shrink the files by 53% the processor only has to fetch half as much from the drive. That takes less time, and can take less time than the decompression algorithm takes to decompress the file, so you may get a speed increase in some circumstances. But backup is the key whether you use compression or not. XP Professional has definitely been the most stable OS I have used since OS/2. I have had it running over two years on my desktop, over 2 years on my wife's desktop, and a year and a half on my laptop without a major crash. I did have to restore to previous state once, after installing a spam-fighting program, but that was it. Anyway, I am very comfortable using XP compression