True, even an anchor chain can be ground off.
I'm using a Mobilistics relay in place of the starter relay along with Rugged Ridge hood locks. Requires carrying an extra fob, hood lock keys, and making one fob press on startup. Total cost of about $200 with the added benefit of keeping creeps from getting under the hood. Seems like this will defeat most opportunistic criminals. My 392 won't start and they won't be able to get under the hood. They can take tools to the hood/locks and swap out the Mobilistics relay with an OEM. Getting into the realm of towing/anchors.
Trying to compare that with the cost and benefits of the Tazer approach. No fob or extra keys to carry, which is nice. Additional uses for the Tazer, for sure, which is a big positive. Easy to enter a PIN- nice. But if most of the POS's trying to steal my 392 can easily defeat it, then it looses a bit of it's value. Have heard that the shield only protects the Tazer from being messed with, but leaves the rest of the cabling vulnerable. If so, this wouldn't give me as much confidence as my current approach. Wouldn't want a bunch of forum members entering PINs for years only to find out that a 5-second trick defeats all of their efforts.