In my opinion, Clifford are the best made alarms I have come accross. Unfortunately like all things electrical, it depends on who fits them. If you hear bad things about a particular alarm then read "crap installer" unless its Cobra in which case its "crap alarm"
If you dont have the skill to fit your own, find a specialist and ask to see some of the installations they have done. If you see a scotch lock, RUN. if you cant see the wires at all then you have probably found someone who knows what they are doing.
Dont get carried away with remote starts and pagers etc, nice toys but the actual benefits are totally out of keeping with the cost and the potential for things to go wrong are massive.
Ask for the name of a satisfied customer with the same car as yours, and ask them how they like the system and the service they got.
Its your hard earnt, spend it wisely and enjoy.