I sure that you can find anything you need on forums, just need patient
Shortly, pitboss is "better" for several reasons. Imagine that you play "regular" on-line game, with turn timer set on 24h, for example. So, you have whole day (even more, because turn timer goes slower than it should be) to play turn. Than, You don't heed to hurry with your turn. Just connect when can and play your turn. It means that you don't have to be on-line for 10+ hours until the game end. No, just 2-3 minutes per day... Also, THERE IS NO NEED TO ALL PLAYERS BE CONNECTED AT THE SAME TIME.
But, PB has it's own "dark side"- one game can last for more than a year. Yes, this is right, and it just because of slow turn timer. Usually, PB is started by a "accelerated start (AS)"- player agree to play first several turns normally, like regular on- line games. So, if they play 3-4 hours, game has to be shortly than without AS...
Search forum for more informations, but this could be a little help for You