I cant beleive no one has mentioned UNGO! In my eyes there are only 2 kinds of alarms, DEI which includes Viper as the high end and Clifford right under it as well as other brands. And then there is UNGO, which in my eyes is the best on ther market. UNGO is the company that owns Clarion, and all they put under the name UNGO is their alarms.
My alarm is a Clifford, it is pretty decent, but I do get quite a few false alarms. I have had my UNGO in a box for a while now and havent had time to put it in yet. For the money, the UNGO MS850 is prolly the best alarm on the market. For how inexpensive it is, it sure protects very well, and includes all basic features as well as a few extras. I should have gone with this but I went for a more expensive UNGO with a fancy scanner.. heh.
Thats my opinion anyways, and I think you will find that Crutchfield would agree with me, .... i think...