Got mine done last night. Honestly haven't had time to play with it yet other then a basic check to make sure things worked.
FWIW, it is highly programmable. You can set a low temp (which is what I thought but nobody seemed to buy) where it'll autostart to warm up. Mine is set to turn on at 0 degrees for 15 minutes every three hours. You can also do the reverse and set a high temp to cool the car automatically.
I also have mine programmed so the shock sensor is off. I hate false alarms and unless you make it into my car I don't want to hear about it.
It also monitors battery voltage constantly and you can set it to start the car to charge the battery if it goes below whatever voltage you set it at. I thought that was a nifty feature. I think it factory defaults a lot of these settings, but you can change them to whatever you want. All in all it has a lot of functions.
As for the Compustar, I have one in my other car and ir works fine although it's claimed range is not near reality, and it seems a bit weak in that regard. Often won't start from inside stores even though I am well within the range limits. Other then that, no issues with it and it's manual.
Still have to play with the viper remotes. One came with dead batteries so can't do anything until I get new ones.