I'm not going to use it until I'll get my preorder on PS3. I'm just nuts for DOOM!
Before anyone says anything: Yes, I did unlock it

So, for now I'm using Kross, and I love that "lil" gun. It has second best accuracy after Bulpdaun, second best reload time after Tampa. The tradeoff is in damage, it has the second lowest within SMGs,
My main weapon is Rhett. Don't know why people would say SMG>AR. Few quick taps on the fire button and enemy is sniffing flowers...from below

Just need to use them within the range that the guns were designed for.
Have fun!