It's fun. That's mostly the limit of its ambitions, but it does its job. The Punisher is bad news, obviously, but so is Deadpool. They're both murderers, with the difference being that the Punisher does it because of his psychotically dark moral code, while Deadpool merely kills for money. Also, Deadpool has a healing factor that makes him immortal and can only be shut up (briefly) by shooting him in the head, which here the Punisher does semi-regularly.
1. THE PUNISHER (here) looks relatively young and clean-cut, but he's still a war veteran who goes around murdering criminals. That's his life. He doesn't believe in romance, hobbies, smiling, having fun, etc. He's not being written by Garth Ennis this time and this version of him is way too young to be a Vietnam veteran, but the character works well enough.
2. DEADPOOL has a Wolverine-like healing factor and is nearly as violent as the Punisher, but he cracks jokes about it. He's "the Merc with a Mouth". He's a comedy character who kills people for money and/or laughs. He's known for, among others, a long-running team-up title "Cable and Deadpool" (where Cable is a stoic, violent, ultra-serious tough guy), so I imagine this comic was aiming for a similar kind of double act. Anyway, at his best, the character can be hilarious. In this book, he rarely rises above "mildly amusing", but I quite enjoyed his silliness and laughed once or twice. Also, he's capable of relaxing, having fun and playing endearingly with children, which you'll never get from the Punisher.
At his loopiest, Deadpool can remind me of the Viz character Roger Irrelevant. "People whose mothers have the same name shouldn't fight!"
Our anti-heroes' opponents include a banker called THE BANK (whose clients include supervillains) and a rival mercenary called TASKMASTER (who can copy other people's fighting styles, so by copying the Punisher he achieves something he normally can't and beats the hell out of Deadpool). Also, THE KINGPIN (Wilson Fisk) gets a one-page cameo and is the scariest person in the book.
The plot's pretty good. I liked the storyline about The Bank and his family, which gives humanity to what could have been comic book nonsense. (I've heard good things about Fred Van Lente and I believe this is the first time I've encountered his writing.) Ultimately, though, it's about our anti-heroes, who are a decent match. The Punisher's grim one-note humourlessness makes him a good foil for the comedian Deadpool, who'd regard "victory" as making the Punisher laugh. Or at least smile. A little? Come on, guy, bend your mouth's corners. There's not really enough here to recommend the book to anyone who's not already into one or both of its two title characters, but I enjoyed it and I've bought some more Deadpool books.