Polycarbonate products are rarely marketed as plastic. It's very high quality material and certainly much better and expensive than common commodity plastics.

Good heat resistance and by far the best physical resistance of all plastics. Some bullet proof windows are actually made of this stuff, but don't shoot your N9 (I doubt the shell is thick enough). It's resistant to most sterilisation methods and biologically inert making it ideal material for various bottles/containers/etc in my research work (microbiology). I've done some long term growth experiments with fungi that partilly dissolve most plastics and then die from released toxic compounds, but can't do anything to PC and thus live long and prosper.

Overall I would say good material choice for a mobile device. Light weight, tough, very durable against continous stress and for a plastic it also feels good in hand (ie. not that cheap plasticy feel of many commodity plastics).