Granted the Systema is going to be is going to be the cheapest and the Operator will be the most expensive but really is it worth it? Which would I enjoy the most, hold up, and keep a good value?
Would you ever want or need a factory Warranty and/or customer service? How good are you at fixing or working on 1911s not covered by warranty? How old are your eyes? Will you ever carry or is this a range gun and/or nightstand home defense piece? Do you shoot at night a lot?
The Sistema has some Gaucho history to it, be it military or police issue. It has BTDT and may be tired and worn... or it might not be. It may be an early model with spot heat treatment or a later model with better treatment. Was it refinished at any time in its life? Loose or tight fitting of barrel @ bushing or barrel/hood at rear? Numbers match?
Loaded w/ night sights and dark (blue or park'd?) finish. Probably, more than likely, a fine shooting handgun, factory will fix anything (to a point, but SAIs customer service is second to none... borderline legendary) no way can you go wrong here generally speaking.
Operator. If you head in harms way or need a light attached for target identification, for home defense or night time practice shooting... well, duh! This one for sure.
Which would you enjoy? All 3 I'm sure. Maintain a good Value? All 3 will drop a little value as you walk out the door with it. Down the road, I would expect the Sistema and Operator to hold best value, but that depends. They aren't making any more Sistemas, are they? Railed guns are hot now I gather, as the USMC is heading that way for a few good men (and women perhaps) via Colt's Rail gun system. But this too, might pass.
So it is... Ya gotta ask yourself... what is it I want/need this thing to do? Answer that, ponder the above questions, check your wallet again and buy all three???