My Moto Droid has a set unlocking pattern. I can unlock the phone by using the pattern lock or the online Mobile Defense Command. If I use the phone to unlock it, it is only unlocked until the screen times out. If I use the Mobile Defense online command, it remains unlocked until I re-enable the automatic lock online and then the phone locks when the screen times out. This would seem less secure then the phone's built in security. Anyone can use the phone until I find out that I've lost it, go online, and reenable the lock pattern. It would have otherwise locked as soon as my screen timed out.
Secondly, with regards to the online lock feature, it doesn't lock the phone as soon as you enter the online command. It remains useable until the screen times out. It only enables the pattern lock that comes on when the screen goes dark. If someone picks up the phone while it is active, they can use it until the screen times out. This appears to be no different then the built in Pattern Lock Security already built into the phone.
The Lock/Unlock feature of Mobile Defense would seem to make the phone much less secure, then the stock phone system.
The tracking feature seems to be the only added benefit to this application as erasing data is not currently available.