Of the books I use:
Bet 365 is my favourite.
Bodog is okay. I just don't like their lines usually.
Pinny's mobile is extremelly frustrating, I usually end up switching to the fullsite version.
Haven't used SI or BetJamaica for over a year, not sure how they are right now.
You guys are forgetting something extremely important
The ones I mentioned all have the sport lets say baseball and lists all games with LINES as opposed to most mobile apps where you have to individually click to each game to get a line and then bet (way too many steps) ..its the number 1 criteria as far as mobile is concerned