5 balls for me anyday...only problem with 5 is if your having a really bad start to the game it's more tempting to do a restart..I always like a strong first & second ball to start the game and if I get a drain early I cant be botherd going through the motions of finishing the last balls when I know it's not going to be a high score. The whole fun or challange with pinball for me is always trying to get a new high score.
Interesting, I tend to find one really good ball will generate a high score for me! So I never give up.