For the N you have it registered through a US company . There is no limit on time it can spend here . My 109 went from G to N about 7 years ago . I also believe you can fly both N and G reg over here so the biggest benefit is not having to have any ratings . For instance I have no twin rating so would have to do a full course including up to 10 hrs flying to get it on my EASA licence . I also have the benefit of being able to borrow any helicopter...206 , 350, Gazelle, Bolkow etc ( I think apart from Robinson ... which I don't want to fly ) without having to get a rating .
Very civilised !! I can't think of any downside....