I am using SleepLess to keep my powebook from sleeping when I close the lid because I keep a VPN running while I'm wireless and it's a pain to have to reconnect as I run around the office to meetings with my laptop after it goes to sleep every time I close the lid. I had dabbled with using insomnia before (http://binaervarianz.de/projekte/programmieren/meltmac/), but I found the lack of interface clunky. SleepLess provides that interface I needed to make insomnia useful. The only problem I experienced is that the version of insomnia that came with the SleepLess package (/Applications/SleepLess.app/Contents/Resources/insomnia.kext) wouldn't load for me. I had a copy of the kext file I had previously downloaded from the insomnia site and replaced the one included with the package and everything works great now. I've only been using it for a couple of days, but no problems so far.