The MACO MK XI resilient shield array has a lot more capacity and the same regeneration rate as the Jhammy MK XI resilient shield array. The bonuses vary a bit, butt overall the Jhammy shield is a lot weaker than the MACO shield. Why's that? Any purrticular reason? The Borg regenerative shields have almeowst more capacity than the Jhammy resilient shields.
If those shields were strunger, I'd use the entire set with my Jhammy ship (1% big buff chance), butt for now I will have to change back to the 2-Borg and 2-Jham set to still benefit from the Pawlaron bonus.
In My opinion, the Jhem Hadar set is junk for PvP. If you use Polaron, then it might be worth it, but like you said, I think the shield is the worst part of the set. The engines are probably the best part. So if you need 2 pieces of the set to get the Polaron benefit, then use use the engines and deflector.