I have the i600 as well, there are a couple of drawbacks I have seen/experienced first the PROS
PROS
- It works as designed,
- The parameter senors does keep people at bay
- It is really annoying and loud
- Installation Instructions is well document (Need to set the day aside though)
- Its fun to set it off as your off in visual view sipping a Jamba Juice and watch people freak
CONS
- It drains the battery in about 10 days or less (The Low Battery cutoff never worked) This forces the need of a battery tender (No big deal really)
- Sensor/Pager whatever you wish to call it is limited in range, if the say 1/2 mile then that is based on NON REAL world situations. My guess is they tested on a flat tarmac with line of site to the bike. At best in a real world situation your looking at 100 yards at best. If your in a building it reduces that distance further.
- I never trusted the panic switch (Aka electrical shutoff) for that reason I had visions of it malfunctioning in a sweeper

Anyway, I figure if I am looking at my bike being ridden away then I got insurance.
Overall
Very much worth it IMO just for the peace of mind and making it that much harder to steal. I always park my bike locked up with disc locks and the alarm on next to unprotected ducati's
A short story
I worked at a company in Sunnyvale for a bit, a group of engineers went to lunch as I watched them walk out the door. Within seconds the alarm goes off my pager is going butt nuts and I glance out the window to witness one of these retards trying to get off my bike. The dude sat on it. I was immediately in his face and the fun began. Well you see there was this language / cultural barrier, I was reprimanded for offending the individual who seem to not understand the American term of "WTF you doing Moron"