One of the aircrafts I use to fly is Rotax912 powered. Due to the engine itself, or to the installation, the fact is that this engine runs always very cold. We've switched to Evans from 50/50 and now we fly with CHT reaching 120ºC everytime. So perfect for us.
If you don't have this 'cold engine' problem, maybe you don't need Evans. But if you have it, Evans seems indeed a good solution. Maybe if you try and switch to 50/50 'traditional' coolant, you will find out your Rotax runs very cold.