When I got the PCX I wiped it down every week, now I leave if for many weeks if the weather is good and the scoot stays fairly clean. All it takes is a minute or two in the wet and the engine area is covered in crap - wish the rubber protection covered a larger area (someone posted they had made their own extender cover to keep most of the crud away from the inner workings). Ah well, just have to live with the reality that a road bike in wet countries will get dirty
The main thing that bugs me is bugs! I have to get them off the windscreen and lights or it annoys me otherwise. I know what you mean about the mud, on my 50cc everything underneath was covered on mud.. But the exterior looked better than when I bought it the problem is for me riding 10 miles into Andover every day on contry roads.. Makes it filthy!