Well, first off I would like to agree with you that is a good price standalone. However, if you want to get it professionally installed most places around here (Missouri) charge you an arm and leg to get it professionally installed if you did not buy the alarm from them. Maybe it's not like that everywhere, or maybe you plan to install it yourself. In which case, this will have no effect on you at all.
The second point is that I personally despise viper security systems (or at least the past ones I've seen). I haven't actually used any of the new ones, however, the old ones range was terrible. I mean, you would literally have to be 20 feet away to start the car or get any readouts about the security status. I thought this personally was terrible, as there would not really be a point to have the status indicator if you were greater than 20 feet away.
I personally do enjoy the range of the clifford alarm systems. Might want to check them out for future purchases.
All in all though, great price listed for the product, however, the models I've seen by viper are subpar.