I'm wearing a pt delta under a pasgt with an eagle plate carrier right now while I chairsoft.
Though since I'm not wearing anything but a g-string I don't feel weighed down and still have pretty good mobility.
I'd have a helmet on too but it'll mess with the tin foil,
In all seriousness for me it depends on the kit I'm wearing and wiith some kits if I want the added weight of a carrier.
Best bet if you want one is get one with pals and you're good to go with a carrier and a modular rig all in one instead of it getting bulky from layering gear on gear.