Basic Composition: Build for classy nomad running just enough stamina to activate the talents vicious and unforgiving and then dumping the rest into firearms. Running CHC mainly across the gear to further eek out as much damage as possible. This build can be tweaked in various ways, but this is how i like to run it.
I prefer having the 9% skill haste on chest roll rather than the additional 5% health on kill option on the chest, but that will be a preference thing as will running crit hit damage on the knee pads and backpack instead of health to further increase your damage potential. The mods leave some room to be played around with to suit whether you'd rather the extra health, more skill haste or extra crit hit chance.
You can always swap the house out for an alternate assault rifle (or another SMG in place of the M4) with a combination of Responsive/Unforgiving/Competent(3rd)/Deadly/Predatory/Vicious/Fierce(3rd)/Brutal/Swift(Hurried, SMG only). May then want additional ammo capacity on the backpack if running two of a kind in place of the resistance. The warlord assault rife with it's exotic perk "Play rough" is a particularly very good option here in place of either the M4 or house.
You can switch AR or SMG damage around on the gloves to have both crit hit chance & damage to suit ones needs should that be your preferred optimal option blessed upon thee by RNGesus.
Lightweight M4; Primary weapon for engagements that start mid to mid-long range. As the weapon is built for crit chance and damage, try to start engagements aiming mid torso to head as to proc the precision talent. Providing you can keep the gun stable and manage your health you can always burst down or take large swabs of health from those trying to close the gap and you can always re-position and use your passive healing to good effect.
The House; Always wins, most of the time... Secondary for when you're in close range and the trump card in most 1v1's. The pairing of unforgiving and responsive is the best combination here but there are other serviceable talents as well as the warlord assault rifle which can be substituted in accordingly.
Double Barrel Sawed off; Standard DZ sawed off shotgun mainly used as nothing more than to build ult. Would rather have Predatory here instead of self preserved but feel predatory most times isn't beneficial enough in pvp to warrant going on the primary or secondary, so it's better here, if you can get lucky. It can be helpful with the additional health boost when bashing a downed player in the middle of a team fight, but any decent rolls where you can land or roll determined in the 3rd slot are more than serviceable.
Most should go with the immunize support station to battle the predators mark bleed and other status effects as well as drop and pop for the 33% heal due to disastrous skill power.I use an emp sticky to combat the most prevalent threats of strikers and predators by stopping the stacks and both their access to healing skills. YMMV dependent on play style. Gas seeker mines, flashbang sticky and conceal pulse are also very good utility options.
Best use of Ult is to go with Recovery Link when solo and any option to fill the void when in a team.