What are your attachments of choice since 4.0?
Champion Muzzle break for any gun that can benefit a lot from having a tamer vertical recoil
Tactical compensator for any guns may need a boost in ADS accuracy for the ranges where that matters. It seems to be a nice couple with the K30 to make it land shots more easily on one distant enough for bullet spread to be a factor.
The extended barrel increases velocity at the cost of some RoF. But A decrease in RoF is also indirectly making the weapon easier to control for me. It is an attachment with almost no real drawbacks.
Light Grip: Because it benefits ADS accuracy at the expense of hipfire spread, I will pretty much select it on any gun that I will not be hipfiring much with. It is really sweet to have that extra tight bullet cone. This ADS accuracy boost used to be part of the Extended barrel but now it has become available to even more guns with the 4.0 light grip.
Laser sight/pointer: As usual this is the attachment for those guns I want to improve the hipfire at. I do not really see much of a drawback as it does not seem to blind others but they can see the a small red beam coming out of the gun so it can definitely betray someone waiting around the corner with a gun pointed at the door.
For optics I will use the Fusion holo or the korba sights as often as I can because they are quite clean good optics.