The way I figure it is: as long as you have something that will stop people from just walking away with your bike as if it's theirs, that's all you really need. Any chain or lock can be compromised. I rarely lock my bike up anywhere, but my bike is...let's just say...heavily used. I use a cheap, light chain that anyone could cut with a decent cutter, but at least they'd have to cut it, which will stop most casual thieves. Pretty hard to cut a chain and have it look like it's your bike to anyone around. A heavier chain will slow down a serious thief, but you'd have to haul it. I assume most serious thieves are in urban areas, and I almost never tour there.