hey. as a newcomer to ny, I have a newcomer question. There are a bunch of different kinds of bike chains for sale on ebay & elsewhere. Is there a big difference between these, holding constant how they are deployed or whatever? So, like, the difference between a chain w/ hex links versus, uh, trapezoidal links ..? or "heat -treated" versus "triple heat-treated boron manganese steel" ? or is that mostly marketing fluff or for real? and what about this lock question--mini U lock from kryptonite or others (as long as that crazy ball point stuff doesnt work) .. or what kind of regular lock ..?

any thoughts on these matters? much thanks & sorry if this has already been covered