Spas raw or suppressed, same OHK ratio.
Lightweight --best choice hands down. Just run, fk a UAV, it can't keep up. Plus who really bases their playstyle on the enemy getting lots of streaks?
Ghost should never be your main perk on a rush class, its a fall back for shooting crap down. Take your training wheels off, if you're dying that much you should reevaluate your approach tactics, or you're not moving as much as you think.
Hardline -- cause its always funny whoring low streaks.
SOH -- 2 to 5 shot kills, reload constantly
SA -- 1 to 2 shot kills, reload after 4 kills.
Obvious choice is obvious.
Marathon Pro -- its got next to no range, your job is to close that gap.