I'm curious about different kinds of metal keycaps. Does anyone actually use them for anything other than novelty keys on places that are seldom pressed? I just got my batman aluminum key from imsto.cn in the mail and I honestly expected it to be much heavier. Its made very well, I just expected heavier. I know that there are a myriad of zinc keys online for sale that sit in the alphanumeric slots, but I haven't heard from anyone who actually uses them. What are the advantages / disadvantages of different kinds of metal caps? Zinc? Aluminum? Would more people use aluminum keys if they weren't more expensive? Thanks!