I think the TV ratings for the US for the DET-ATL game were very high. It was very cool to watch a game at 9:30AM, and it helped kill time before the games at 1. As for attendence I'm not sure about the whole 5 years, but the announcers said before the DET-ATL that they had yet another sellout in London.
I personally would like to see the NFL stay the way it is in the US. That's a very slim chance though with money being the main factor.