I bought one last summer....
No problems altho' not been riding through the winter.
My subframe broke at a track day (2005 999s). Complained to Ducati. No joy. Needed to replace and couldnt find a mono on eBay in UK. Plus didn't look that good a design anyway. btw mine was already the Ducati modded one with an extra 'plate' welded over the lower tubes. Didnt work clearly.
The USA one came fine - have to pay duty on it mind. I'm writing this at work so can't remember the exact difference, but i remember when fitting that it was an improved design. only slight complaint was the paint finish was more glossy black than the more satin black original.
If you need more I will dig out more info. Not back home (work) til Monday though....