I say go the 35's.
What it means is that you will have extra traction and clearance so that you don't get stuck in ruts and holes that idiot drivers with 33's and less sit in and spin their tyres to eternity while they chop the crap out of the tracks and generally destroy the place. Although 25mm doesn't sound like a great deal - in practice it is a lot as it makes the difference to clear the holes and humps that others have made and had to be winched and snatched off.

