PGL does not use 2-EHA....Dexcool does.....2-EHA is great for cooling systems but has shown to be a 'plasticizer' of certain gasket materials (it softens them). Newer gaskets are supposed to be able for 2-EHA without deterioration but I would still use PGL if I had a choice. PGL is probably the closest to a 'universal' coolant that you can find.
I think that PGL says that it can be added to any LL coolant but I would use it straight (50/50 mix with water) to get all the benefits from it....