Hi JV,
I have a Sinar 54M I bought used, I sent it back to sinar in August for service after I damaged it. Sinar support was top notch and easy to reach. The turn around time was a bit longer than i like because the factory was off for part of August i was told. Aside from damage i dont think there would be any reason to send it in for service..I know plenty of Sinar users in the U.S. no worries, I shoot with a non AF rollei 6008i.....if anything I would be more concerned with Rollei service ...lot more moving parts in the 6008 !
Regards,
Dennis