I have owned both alarms.
My current GSXR has the RFID i900 one.
I got it for $300 after talking down the guy in price, new at my local motorcycle shop.
It auto arms itself basically, when I take the key out it arms.
Thats basically ALL thats different, the keychain and the alarm has RFID chip in them.
Its really nice though, you can't set it off accidentally because when the receiver on your key is near the bike it knows its you..
its really wierd how it works, I can be next to it and the garage door shutting can set the parimeter alarm off, but me standing next to it doesn't..
its like a genius alarm ;D
Its better than the previous one imo because the receiver is better in looks and functionality I believe, and arming the alarm isn't hard but being able to just get on without having to disarm it is nice. I've never had an accidentally set off as i havent got on my bike w/out keys before