I use P.E. heavily mixed with other factors in my baseball handicapping. It is certainly a good base to start from, BB. Then you can gradually expand a systematic approach from there depending on past trends or historical data.
I've never tried P.E. in football. I suspect it wouldn't work because there arent enough games. I would be willing to bet that P.E. can be a real good base for basketball or hockey as well simply because of the amount of games played.