If done properly aircraft maintenance is expencive be it FAA or CAA but in the long run it is cheaper to do it properly than than to try to save a few dollars.
The FAA dont demand so much in the way of paperwork and dont charge large fees for everything that they do.
Due to the compleat joke that is the JAA pilot regulations i would advise you to keep the aircraft with the FAA as you will have less hassel with the paperwork both flying and maintenance.
For most people the fact that the FAA IR is not out of site cost wise is the biggest advantage but be warned the ground exams may be easy but the flight test was one of the hardest flying skill tests that i have taken because you dont know what the check airman will ask you to do next , unlike the british IR were you know exactly the form of the test and have spent the last three weeks practicing the whole thing.