Cambodia: I've most ridden around the North West, Anlong Veng/Samroang/Pailin. The roads are horrible, unpaved and dirt. I've been on a couple paved roads from Poi Pet to Sisaphon and Sisaphon to Battambang. Sisapon to Poi Pet Sucked something awful, lots of pot holes lots of dust and fast traffic, maybe it seemed worse as I was expecting a paved road. Sisaphon to Batambang was fine.
But the thing with Cambodia, is that even though the roads may suck the people are just wonderful. With everthing that they have been through over the past 30 something years. It was just such a good experience that the bad roads only add ot the charm of the place. The food was good also, Thai food seems to get all the press but Cambodian is right up there in my opinion.