Depends on what you bring to the table in actual play. Dragon spam will of course wipe out anything but doing that way you eat a -800-1000 score. 40ish dudes(difficulty 4) With say 1/6th being marsec bodyguard clones, another 1/6th being Humanist Stormtrooper clones, 2/6ths Marsec operative clones, and the rest government agents. Armed with a mix of lasers and heavy weapons with a dash of plasma and gauss. And multiple tanks. Considering every kill not on the tanks is negative score, stunning and making sure they stay down with that many sturdy targets is difficult.
The Rebel version is much easier because aside from the general the rank and file are the civilians from pogroms with the same laser/heavy/plasma&gauss loadout. The absence of armor, the tanks, and no penalty for kills makes it much simpler to handle.
Keep in mind its 30 turn timer to disable(stun or kill) everything. If you don't win before then you lose everything you sent. You also have no option to retreat. The difference between the 2 versions i observed is so large that it will lead to false impressions depending on which you see first. I saw the rebel version first and was like okay this is balanced to when it first unlocks. Government version however would probably bitch slap the same force that would be challenged by the rebel version.
I wasn't talking about the eurosyndicate missions. I always found those less a matter of being challenging because of the enemies, even on the government targetting missions, and more of it being challenging because you only have about 30 turns and they're always urban maps with big buildings that have so many nooks and crannies and you only have so much energy and TUs to burn on looking through all the doors. I was talking about the Silver Towers map. Just don't research them before you unlock MAG rockets and can level the entire building.
But yeah, as to the scoring that the mission offers you compared to the payout, it's really shit. It shouldn't be that difficult to create a new race that uses the same names, sprites, stats, and loadouts as other government units, but they have different scoring when you kill them. I get why the provincial government that you're fighting against wouldn't be too happy with you killing their people, but the Eurosyndicate being happy with you should balance it out, since scoring represents political favor and the Eurosyndicate is very wealthy, and therefore powerful.