Disappointingly boring...
You start out as Victor Vance (Lance Vance's brother from Vice City) and he is in the army. The bad thing about this game is your guy is apparently a "good guy" which makes it even more boring because you don't do all the good missions like on Vice City.
The graphics are the same thing as Vice City. There's no new vehicles and the main player character is the only new character. There's no new experience which causes it to be boring. The whole game is based around one thing and one thing only. The Mendez brothers. It gets boring without there being multiple boss fights throughout the game. Instead there's like 3 right in the end and those are the only ones you get.
With only one storyline, one new character, and no new experiences... this game is the most disappointing Rockstar game ever.