coloured pvc windows
One thing to ask the supplier (& check yourself if possible) is whether the colouring of a pvc frame is actually just a top layer - or whether the pvc is coloured all the way through.
In general, pvc windows just have a very thin layer of coloured material heat bonded to the outer surface. Then, when they get scratched - and they will - you can see the white pvc through the outer colour.
With cream, this might not be so obvious, but I have seen scratched red pvc frames which look terrible with the white background showing through.
Laoise