IMO it is good, yes, but bear in mind the co-op is only local NOT over Live. Having said that, I would say it plays more like Gears than Army of Two. Obviously it's not as smooth as Gears, but it's that sort of thing.
As I remember there are no co-op moves ALA Army of Two, but you do get different achievements depending on which character you are. Which means you HAVE to play 2 player local if you intend to go for the achievements.
The online mode is quite good too - it's a bank heist where you go in as a team, and choose whether to help your fellow robbers so you all get out, or go traitor, shoot them in the back of the head and take the money. It's good but the community isn't amazingly active any more so it takes a while to find a game sometimes.
For the cheap price you can grab it at these days, I would snap it up. I paid about £25 for it and wasn't disappointed, and I'm usually a cheapskate!