Everyone has their own favourite approach when it comes to FPS gameplay. The best weapons for you depend entirely on what you want to do in the game. You can have multiple load outs so don’t worry about being stuck with your first choice. You can always change during the game at a Supply Depot.
I recommend you always have either an assault rifle or a machine gun in your load out. These guns seem comparatively overpowered and you’ll find the majority of players use them. The rocket launcher is pretty useless and if you want to use explosives go for det packs every time, they are great fun. Happy Hunting!