Please to hear the positive replies here as this is the set I'm working towards although the price is high I'm sure it's going to be worth it and that was BEFORE I'd factored in the extra damage from the cutting beam+tractor. As an additional I use aux to batt with 3 x VR Technician DOFFs for a 30% reduction on all BOFF CDs, it adds up to a very nasty cruiser setup especially on the fleet Excelsior with a TAC captain.
Borg deflector and engines I think are amazing. I miss out the shield as I think it is underwhelming along with the 3-set bonus, so I substitute it with a MACO shield for survivability, though I would prefer an adapted one. The cutting beam and console I reckon are vital, and the 2 set bonus from them is also sweet. Have yet to try out the omega torp or the 3-set bonus, but to have a ship with a high capacity shield, a 2-set AND a 3-set is nothing to be sniffed at.
3pc borg would be nice but I can't get over how bad the shield is. If I were to dump the shield the rest of the stats are still meh except for the hull heal. I'll take the actually decent stats and a good 2pc to boot.
Not sure to be honest anymore when it comes to combos. I always used borg engines, deflector and maco shields. But I plan on trying other combinations out in the near future to take advantage of the set bonuses as much as possible.
Since I got Tier V reputation in Omega now looking at the specs (not sure if it is a graphical issue or not) the improvement to the MK XII over the old STF EDC MK XI is minimal. The engines it shows there is no change at all between the the MK X, MK XI, and MK XII. I guess if you go with the MK XII deflector and MK XII shields you would need the MK XII engines to for the set bonus?
I really wish they would give you some sort of turn in bonus though for getting the Mark XII. By this I mean have 2 purchase slots for the MK XII items. One with the expensive cost and one with a reduced cost because you turn in your MK XI item with the upgrade.
For me personally while the MK XII set is nice I honestly can not see doing 36 Elite STF runs (avg 75 omega marks per) to get the 2700 total omega marks for the set. Seems too high to me to me.