Works spectacularly well when you FOLLOW THE INSTRUCTIONS and set up the voltage and frequency settings well. It has saved me from upgrading my MBA-revA and therefore saved me from upgrading and spending many dollars!
It prevents my MBA-A from climbing up to 100C, keeping it cool down to 75C max with power savings and hence battery savings such that after 650+ cycles still has 88% health. (The 12% loss is probably due to me keeping it plugged in AC all the time).
I can comfortably keep it on my lap and even reduce the temps further down if I find it too much on my legs. It extends the battery range very well; it IS, without a doubt, the BEST $10 I have spent on anything to do with an Apple.
As for all those whiners complaining about the TOS - Harden up, princesses.
You pay for a $1000+ machine that rocks yet complain about a $10 app that literally saves it from losing a core; preventing it from becoming half of what it's worth; get real.
The pitiful $10 asked for this app is basically a donation! It is really worth $50 for what it does. The TOS is there so that it doesn't cost $50; the licensing server prevents pirates from ripping it off.
Kudos to the Marcus (the developer) for sticking to the TOS. I've asked for help before on some licensing problems when updating & purchasing another license for my MBP 2007 and I've received it.
Marcus is likely a one-man team - come-on, he's got a life too you know! Sometimes what you need to do is RTFM. There are countless webpages floating around that will help you get there.
I would probably only offer a couple of suggestions:
1- Make the app work in such a way so that the finding of VF pairs is almost automatic; with the user only needing to HARD-RESET to continue the next test when the kernel panics.
2- Please make it work for OS X LION. My MBA-A is DYING as I speak (and typing this). Oh how good Coolbook is - I'd pay $5 in a sneeze to get it working again. Please let me know mate, I know you're probably hard at work finding a way... Else it's gonna be a new MBA for me. (See? $5 can potentially save me $1000)