Which is the best machiny out of all on mw2?

i would like to know which is the best machiny on mw2 i have just started using the m4 because it looks pretty good but i want a machiny thats does alot of damage quick firerate not much recoil and also doesnt take so long to reload i have used an acr tar and scar h before and im 7 levels away from ak47 is the the best? thanks :)