Pros:
Tech per turn is doubled
Market commissions replaced with a 5% VAT that works in the same way.

Cons
Humanitarians stop every attack (ofc)
Oil rigs produce nothing. (let it stay in the ground)
Burning oil for private market units is impossible (Carbon cap)
Exploring gains -50% (nature shouldn't be exploited)
-40% food production (Organic, non-GMO)
Food cannot be bought from the market (all others produce GMO and non-organic)
Military units cannot be bought from the market. (ofc)
Workers strikes are x20 more frequent. (greens are basically marxists with a fancy costume)
Teching is restricted to non-warfare techs, Spy, SDI, Weapons, Warfare, Military and MStrat cannot be teched or bought (self-exlainatory)
Teching is random, among the non-restricted techs, you cannot chose what to research.(While the greens like supporting research, it is generally not the research that results in increased productivity that they support)
1% change of switching republic, dict or fascist every turn taken, with switching losses. (we don't know yet :P)