There are only three common bases for automotive anti-freeze additives to water:
Alcohol
Ethylene Glycol
Propylene Glycol
Alcohol was used for many years but, because it has a lower boiling than water, it has to be replenished regularly and fell out of favor around the WWII era.
Ethylene Glycol has a higher boiling point than water, a low freezing point, is stable over a wide range of temperatures, reasonable (but not as good as water) thermal conductivity, and a low viscosity and is therefore by far the most common coolant base.
Propylene Glycol is inferior in every characteristic to Ethylene Glycol but one: it is less toxic.
So, both Toyota and Dexcool are Ethylene Glycol.
The difference is in the additives.
Sixteen years ago one of the posters did a nice job of summarizing the differences at the time:
Coolant Families
and, with the exception of outdated urls, it is still a good summary of the different coolant approaches.
Asian makers use phosphate based additive packages with no silicates and organic acids.
Dexcool lacks the phospates and uses different organic acids.
Switching coolants means doing your own science experiment to see how it works out.
