I found the LAW in MGS:PW very satisfying. As satisfying as a rocket in a handheld game can be, at least. I liked everything about it. It was one of my main weapons when retreading all the bosses for AI memory boards. I never did unlock the Dragon
On the topic of TF2, I found and still find the Black Box to be the single most aesthetically pleasing weapon in the game. There's a reason why the Tankbuster set won the Polycount contest and the designer got commissioned by Valve for some later designs.
Gameplay-wise it handled identically to the stock launcher as the only adjustments had it holding one less rocket, and healing you upon striking a foe. It also had a snazzy new firing sound which was rad as fuck at the time remember getting excited over little shit like that?, but the Original sounds better now.