I had a Ravelco installed several years ago shortly after I bought my '02. It came without any antitheft device.
At the time I was living in a sketchy Sacramento neighborhood, a city with higher than average vehicle theft to boot. Following some research it looked like the best option out there though I have not had any break-ins yet, fingers X'd. I try to keep my rig looking as unassuming as possible which seems to help. It was a bit steep ($450 for the complete install) but cheap insurance, IMHO. Plus it doesn't seem to be a very well-known system which may further deter thieves.
Wish I could've watched the tech do the install but I had it done while at work. 99.9% of aftermarket electrical installs I've seen look like complete hack jobs, so I had my reservations about having someone else do this. I must say this guy did a very clean install and it has worked flawlessly through repeated use. I believe Ravelco also backs their product for life which was a major bonus since after all, they're splicing into some pretty critical wires within the fuse box.
So yeah, I'd recommend it. Sure, nothing is effectively theft proof, but I've no regrets about this mod.