Here are my thoughts on the new lab and it's best loadouts as opposed to normal TDM, not a SP like essay but hope it helps.
AK: It has been weakened due to stopping power being less valuable and it's damage hasn't increased by much.
M9: It is around the same as before when compared to other weapons.
G-MAL: Has had a big buff with the 'pop up' technique being alot better.
FAL: Has had a slight buff and is very powerful.
Dragon: Still a 2HK so best of sticking to other modes when using this gun.
Para: I believe it is a 2 bullet then punch so still valuable, but is around the same as it was relatively.
Tau: Has had a great buff in terms of blindfire as was it lacks in 100% health modes is consistency, you can now 1 bullet 1 punch people like the post 1.04 U2 para (assuming a body shot).
Well Fleet Foot and Scoped-In are not as good due to being able to tak less damage, only really viable with the G-MAL.
Cloaked has become (if not already) the #1 booster similiar to post 1.05 U2 with SA.
Boosters like Power Hunter have become completely useless.
Well as a overview the PW kickbacks/grenade kickbacks have had their usefullness decreased due to no noticable damage increase.
I believe 'Gotcha' takes the top spot due the PW and grenade kickbacks effectiveness being reduced and Smoke Bomb being nealy pointless (always killed through and KD dosen't matter).
Well the same hats are the best; Headshot damage, Cloaked level 1 etc.
Written in about 10 minutes, but hope it helps people to find a loadout.
with headshot damage +25% hats:
TAU: 1 headshot kill!
FAL-SS: 2 headshot kill!
G-MAL: 1 Burst
AK-47: 3 headshot kill
Para9: 3 headshot kill
M9: 4 headshot kill
Micro: 5 headshot kill