Upload & Sell: On
I'll admit I'm as bad as anyone (probably worse than most) at loving me some brand-new, just released gear. And I'm always aware that that there's an inevitable early-adapter penalty that must be payed (see http://www.lensrentals.com/blog/2011/01/stuff-i-wish-id-never-bought Rule # 3: don't be an early adapter).
No question there are some issues with the 5DIII, like with any new camera, but we're up to 100 copies rented out already and it's really been fairly trouble free. We brace ourselves for increased problems and complaints when new cameras start renting, and we're just not getting any with the 5D III (or the D800 for that matter).
We had far, far more problem reports when the 7D was released than we're getting with the 5D III (perhaps because of a different level of photographer using them, but still it's impressive). Back in the day when the 1DIII first came out we had over a 50% complaint rate. The 5D III, at least so far, has been virtually complaint free - except at first when people complained they couldn't extend the rental and keep the camera longer because our stock was so tight.