You don't need dedicated servers any more, so I can happily host a server one night. I can slap a Mumble or TeamSpeak server on the spare PC for it, too.
I used to be pretty in to United but I never really played Nations - I didn't like the Starforce. I'm slowly working through the Nations ones in an effort to put some relevant times on the board.
PS for those of you with only the freebie version, the paid version has different car types, different game modes such as Platform, Race, Puzzle, and more. It's WELL worth it.