The last Rambo that came out has the combination of mindless violence and the feel of a stoic Rambo, and an overlying message in the atrocities in Burma. I liked it a lot ,but like Rambo: First Blood, there's a story there, but kinda not really.
Rambo 2 and 3 are almost identical, with superman Rambo taking out the bad guys. I like them, they're different, and they have some awesome moments. Rambo 3 is almost exactly like 2, but Rambo is wise cracking and sarcastic, which was pretty funny. Rambo 3 also had more badass moments in them, but less gauntlet superman Rambo of 2.