Well, my main preference is to run and gun but I do enjoy sniping as well. I've kinda found a mix between the two.
PSG
Ballistic Knife
Tact insert (if domination, otherwise jammer)
Smoke
Tomahawk
Lightweight Pro
Scout Pro (Sometimes Steady Aim Pro if I just want to knife) - very few people are ready for a sniper to come charging at them.
Marathon Pro
This class is insanely fun, and decently effective when used right. With scout pro, you can adapt to any situation and seize all opportunities that may be at range.