I have no experience with Guarder's nylon products so I can't comment on those. Anybody with experience on this care to comment?
If you already have the pouches I recommend going with the modular vests.
If you wan't to go with BHI, I'd bin the Omega vests you mentioned because they're still using the ALICE attach points. Go with the BHI STRIKE modular vest such as
STRIKE Gen 4 MOLLE Omega Vest or
STRIKE DOAV Vest
If you can spend a little more you can't go wrong with the SEALs Action Gear modular vest (made by Eagle Industries).