I have the Avital 5303 remote start plus security. It has an lcd remote which is great for knowing why the alarm has been activated. I installed it on my own this past January and have had zero issues. If you go aftermarket, you really need to do a lot of research on wiring, then some more. There is a lot to know about signals, voltages, and certain wiring shortcuts that you can take. This is all assuming you will be doing a self install.
As far as the actual unit, its pretty good - theres a few things that bother me, but it's more because I am very picky and set my standards too high. I live in a condo building (8th floor) and my car starts fine from about 300 yards away. Only issue is depending on my remotes battery level, I may not receive the reply from the car. Another thing that bothers me is if I wait too long to unlock, I have to be really close for it to let me unlock it. Its a feature that they have built in. I can get cabin temperature on my remote by using a specific button sequence. Overall, its good enough for me. I dont need a mile long range, so im happy. I gripe that it uses AAA batteries, but I get about 2-3 months of daily use from 1 battery.
Also, if self-installing, don't buy a DEI bypass, check Fortin's website if they have an application for your car and buy theirs if they do. The key-override-all works great and is programmed by you turning the key and pressing buttons, so no need to buy a programmer for an additional $60-80. Plus of you buy their product, they give you 1 free wire guide
I bought mine from Sonicelectronix.com . Paid $112 with free shipping. Cant beat that for all the features you get with this unit. I like DEI's actual systems, have had many, just HATE their bypasses.
Let me know if you need any more info!