I think as a general rule, if you are scalping or middling, you would be well served to try to places your bets at two different books.
As far as sporsbook.com, last year during football they offered 10% back on all your online wagers placed on tuesday (can't remember if the bets had to be placed on tuesday, or if the game had to happen on tuesday or both). So you might want to keep your eye out for some good promos