Monster Hunter is awesome!!

[Jumpin]

My opinion;
Single Player, multiplies the fun factor by 1.
Online multiplayer is somewhere around 20-50% more fun, so 1.2-1.5
Local multiplayer is more like 3X to 10X more fun, so a score of 3-10 depending on the players.

So in my opinion, if you like Tri, and don't have a PSP, if you have a group of people to play with, you're going to have an absolute blast with 3DS Monster Hunter in local multiplayer mode.