Nope. No drawbacks. I build these Daytonas myself, and if they need service, I simply uncase, and send just the movement out. In fact, I have this El Primero in with Ziggy right now for a service:
http://www.rwg.cc/members/index.php?showtopic=18140
Farthest thing from the truth. Rolex has no real power in this sense. Watchmakers aren't selling watches, only servicing. Rolex can't zing them for anything since it's not illegal to service or own a replica watch; to most independents a watch is a watch, and the money coming in for a repair still pays the bills. About the only threat they can impose is pulling their parts account, which, as we all know is no longer the case since Rolex stopped distributing parts; the only way one can obtain parts and service is through NOS with certain parts houses, the secondary market (which is highly inflated) or through any of the RSC, with a valid genuine, of course.