Well you can still continue to use till somewhere around March nxt year (once you have made up your mind that is) (Note : I am not sure about the date , do check Microsofts site or your e-mail from Microsoft. It tells you when the product expires). Once it has expired , it will shut down for every 2 hours or so , randomly.

Its between day and night. One is meant for testing purpose and the other one is meant for production use. You dont get patches , fixes , etc to be delivered for RC