I have both styles.
The Omega trigger is easier to work on. You can swap out the safety for decocker, the decocker works in the opposite direction of the traditional 75 trigger. IMO the actual trigger shoe is better, its flat with a slight curve, the 75 style can have a fairly curved trigger shoe, all my 75s get the 85C trigger. Out of the box the Omega is considered a better trigger. Omegas will also come with better sights.
The 75 trigger is harder to work on, but once you take one apart its pretty easy even the decocker models. The 75s are far more responsive to trigger jobs then Omega triggers. A 75 with trigger parts/work done from CGW is a thing of beauty, they will ruin you!! A 75 can be turned into a SAO trigger, an Omega can not.
To me it boils down to one thing, are you gonna ticker with the gun? If you wanna get a P01 for a carry piece and want no part of trigger mods get the Omega version. You want a P01 that can rival most 1911 triggers in SA get the 75 and Cajunize it. For me the best system would be the 75 with an Omega trigger shoe.