I get the mottling every now and again but, to be honest, it's my own fault. If I've had the patio doors open and the room is cold, and the prints have been sitting ready to be used then I may end up with the mottling but I put that down to them being either damp or cold as it only ever happens under those circumstances. Here's some photos of a case I've literally just finished making:
EDIT: Apologies for the quality; I hate photos taken using a phone but it's almost time for the kids to go to bed and I don't have time to take proper photos :\