Keep doing what works, but definitely ADS is more effective. Trust my .70 k/d

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As for nooby, I know I don't even think about that stuff. Some people just don't like getting owned so they complain.
Other weapons, check the battlelog and it will tell you how/what you need to unlock those other weapons. Most of them come from assignments.
http://battlelog.battlefield.com/bf3/gate/And Kreater, I still say the new close quarter maps are more fun than the original. I don't know if they are available for less than the $50 premium.