I'm an excellent sniper, I'm ranked 18/50 online, after they reset the ranks.
-.-
But, I'd say if you are actually GOOD at halo, the BR is excellent for killing, with 4 shots to the head from far away equalling one kill for you.
Duel weapons I would stay away from, the inability to use a grenade at a critical time can cause your downfall.
Stickies are grand.
If you are good with stickies, nothing will make your enemy madder than seeing "You were stuck by ----"
Shotguns are entirely over used, my little brother is 10 and can pwn with a shotgun, it's a very easy weapon to use.
The sword is good, if you know exactly how to use it, but if you have a sword and your enemy has, and is good with, a shotgun, beware, they can kill you while you are lunging at them in the air with the sword.
The carbine is a good weapon, but if you are new to the game, I wouldn't advise using it.
The spartan sniper is better than the beam rifle.
Rockets = TOTALLY nooblike.
Anyone on this earth can kill someone with a rocket,
I mean come on, it's a rocket. << -.-
Eh, I don't know what else to say.
It's a game that if you are good at, you love, and if you suck at it, you hate.
I love it.