The Viper is a nice alarm, but my personal opinion you that you can get the same or better quality for less $$$ with other brands.
I've had easily 10 times more Viper remotes fail than Autopage, it's not even in the same ballpark. The new remotes are a big step better though and may not be so prone to failure.

When you buy a security system online just consider all the situations first. Get installation quotes and compare that to the installed price of buying one from a shop. Also remember that if you're buying from an unauthorized dealer you may have no warranty at all and even if you do be prepared to pay to get it removed, shipped off, and reinstalled. Just be aware, thats all!