Spend the extra $50-100 and buy a captive bred blood FROM the breeder. Think of the overall costs of the animal in factoring. The cage and food for either snake will cost you 5-10 TIMES the cost of the snake itself...so what's an extra $100 to get a quality captive born and bred animal? You spend the $75 for a wild caught snake that might have ticks/diseases and is probably more aggressive (on average) than the captive born/bred counterpart. In my mind it's a no brainer.
As for burm or blood...I'm a bit partial, but blood any day of the week. They are impressive snakes that don't eat a tremendous amount (adults eat 1 med/lg rat every other week) and don't require a huge cage.