I have 4x12 frayed spa green tiles in my kitchen. I just wipe with a hot soapy rag and spritz with wiindex like product.

Ours has been in since June 2007. No scratches at all on ours. There are a couple of minor nicks; one might have been there before install (or I did it chipping off an errant blob of grout or a fused glass bit on the tile surface), the other probably caused by the pot-filler faucet. They are teeny-tiny, and not even visible unless I'm really looking for them.

Once in they should be fine, but make sure you have an experienced tile installer, as glass can be tricky. I had a very bad install by a so-called tiler our last builder used. Chipped un-even edges and later had it all ripped out, but the few months we had it in, the care of the glass was very easy and no scratches appeared with use.

Chipped or scratched tile aren't that difficult to replace. Save a spares, get the tile you like and relax.