I have run a game of Eclipse Phase at an RPG convention in Sydney. I found it to be a very cool game, the setting in particular is very interesting and varied however the rules are a little complex for people who want to just try it.

There are a lot of bits which don't quite fit into hard sci-fi - aliens, psychics, nanotech that works like magic. However, it's pretty easy to leave these out, except it's difficult to know how realistic nanotech would work. I doubt we'll ever use it to create mundane things due to energy constraints, but I guess in the context of the game it works.

Where the game really shines is in dealing with mind uploading, "re-sleeving", virtual worlds and psychic surgery - you can copy minds and re-merge them, even edit them to some degree. It gives a lot of scope for games that work with meta-levels of reality and manipulation of minds. I would like to explore possible transhumanism using it if I ever get the time to.