Have you had to use it? or have you tried it?
I'm actually so impressed by it, I included it in the Modaco custom ROM I've been using since I got the phone. Works flawlessly, and when included in the ROM, it's very difficult for anyone who's not familiar with the phone to get rid of.
It'll track the phones location by GPS, tracks which SIM cards have been used in the phone, tells you what calls have been made, lets you remotely lock the phone, and allows you to remotely wipe the phone in the worst case scenario.
Oh, and you can back up your messages, contacts, call history, to the WaveSecure servers, and you can restore them from the phone, which is handy when messing around with ROM's and the like.
Definately worth having a look at, and IIRC, they do a free offer at the moment so you can use it free for a year, but you've gotta register on their website and install the software by the end of the month.
EDIT: Register by the end of March and they give you a free lifetime subscription.