Don't buy this unless you love the characters Bruce Campbell play, or you are a fan of Burn Notice. I happen to be both, so I enjoyed this prequel. And it was fun to see the characters from BN and the Glades who made small contributions.
Agreed that the plot wasn't that realistic, and "Sam Axe" is not what you would believe to be a Navy SEAL (Although it's interesting how many TV characters are playing former SEAL's) . But its also smartly written (like Burn Notice) and has a great mix of sharp dialogue and McGyver-esque tactical weapons and scenarios. Sam is a character you want to go have a drink with, and will stick you with the bill as he walks out with the ladies. But its a fun character, that is not full of macho MMA moves or overly violent gun fights. Now you know why Michael Westin has him for a friend.
The bonus stuff is okay (again you have to appreciate the dry humor) and the whole thing lasts less than 2 hours. A good watch if you like this genre of TV shows (Spys and their interpersonal issues).