To be honest, my biggest worry is mixing coolant types, but if one is doing a complete flush, not a drain and fill, I cannot find any credible information that a different, modern coolant formula caused any problems, except in some heavy duty diesel applications.
I understand that going OEM is the safest bet, but on the other hand, most of the components used in the cooling system follow industry standards, so chances of having incompatible materials with a specific type of coolant are very low.
Perhaps that is why a lot of owner's manuals have some sort of generic statement about coolant like in my Mazda:
"The engine has aluminum parts and
must be protected by an ethyleneglycol-
based coolant to prevent
corrosion and freezing.
DO NOT USE coolants Containing
Alcohol, methanol, Borate or
Silicate.
These coolants could damage the
cooling system."
Although I find the low low silicate G-05 works excellent in my Mazda.