Quoted from PinballFever:
I think it depends on the game too. Some games may play better with steeper playfield and some may play better with a shallower pitch. Try different degrees and see how you like the gameplay.
Totally agree; I crank up angles on my mid-seventies WMS games (Gulfstream, Super Star, Dealer’s Choice) to about 7 degrees. Woodies stay at about 3.5.