From an industry trade journal:
"Polyalphaolefins (PAOs) To See Competition From Shell
PAOs have long been the premier base stocks in terms of performance. Although challenged by Group III stocks, PAOs still represent the superior product in the industry; however, Shell Global Solutions is developing a fluid to give PAOs competition from an economic and performance standpoint.
The fluid, known as ethylene-alphaolefin polymer (EOP), was originally developed by Pennzoil-Quaker State, now owned by Shell. Shell recently scaled up a pilot plant to produce EOP, making
viscosities comparable to PAOs, like 4 and 8 cSt material. At a recent presentation in Ostfildern, Germany, a Shell representative stated EOP is synthesized from ethylene, propylene and butene using a single-site catalyst, and the reaction products from the process exhibit comparable physical and chemical properties to PAOs. Even more, the feed stocks and manufacturing costs are significantly lower for EOP than PAOs.
However, some issues exist with EOPs that must be resolved first, of which additive solubility and seal compatibility represent the highest priority. Finished costs are expected to be 20-30 percent lower than PAOs for the 4 and 8 cSt material, with higher viscosities being as
much as one-third the cost of a PAO. Initial applications are targeted for high viscosity gear oils and some other industrial oils as well as some premium engine oil formulation."
I think it's highly likely that they resolved any issues with additive solubility and seal compatibility. Don't know if EOP has any properties that are superior to PAO. Maybe MolaKule will chime in.