I know that Clifford has been around for some years. I‘ve also heard a lot of people talk about Viper. I do not want to go too cheap on the system. This is one of those cases where I think you get what you pay for.
To be completely honest the brand of alarm matters much less than the experience of the installer. Most installers will take 15-45 minutes to install a car alarm, these installations are a complete pile of you know what. Every week we have people coming in for us to repair other installers horrible installations. A good alarm should include a hood lock so that a thief cannot simply pop the hood and disconnect the battery in order to the override the alarm system. Glass breakage and shock sensors are both great tools to combat a smash and grab. We install tilt sensors on vehicles that are worried about their wheels being stolen. The tilt sensor will trigger the alarm if someone starts to jack up your vehicle. With today's modern transponder vehicles most are stolen by the use of a tow truck, the tilt sensor would sound the alarm in this case. To give you an idea of the difference in installation we spend two days on a car alarm installation, we hide all our wiring and the brain of the alarm. All our connections are soldered, most installers will use scotchlocks which are prone to failure but allow an installer to do a 15 minute alarm install. Back to your question, clifford actually went out of business awhile ago and DEI bought their technology. DEI also makes viper and other car alarms, any of them are going to be fine. Also I would not suggest a remote start on any vehicle, you are basically playing with a loaded gun. Imagine being under the hood of your car and leaning over to have the remote in your pocket start the vehicle, very scary. There are ways of making it more secure but unless I lived in an area with huge snowfall I would forgo this feature. If you do decide to install it make sure there is a hood switch so that the system cannot be activated with the hood open.