BassMan

A heavy hardened chain around something solid is of course very good, the only problem is where to store the chain when driving. You don't want a heavy chain rattling around and possibly also disturbing your balance. If you have storage box(es) on your bike that could work, but otherwise a rotor lock of some kind is the most convenient. It's sort of the minimum most insurance companies accept. For me that's the deciding issue, together with the convenience factor.

If you have to park the bike outdoors for any longer period, say overnight, it surely needs to be chained to something heavy, and both wheels secured. Depending on where you live I'd go as far as to say that if you can't garage your bike when not in use then you should perhaps consider not having one in the first place. I hate leaving the bike even for an hour or two when in town.

The world is unfortunately full of people with no regard whatsoever to what's yours and what's mine, as well as frustrated people that think they will feel better by messing with someones parked bike...