Zog it, don't make me choose! I'd probably have to vote shootas, but I just barely favor them over choppas.
Why not have both, especially when you're nob/meganob? Choppa iz da bezt but snazzgun 'n' deffgun are alzo great!
Sneekin' den quick choppin' quiet like... then taking da 'umies shoota and den... well Dakka happens.