If you use the waterless coolant it doesn't boil until 375f and can be run at 0-psi so less stress on your hoses as well. but the bottle is nice so you can see your coolant level and makes filling easy. this is also a great solution to adding a stat to a KX500 since the head outlet is only 1/2 inch from the radiator inlet.
I thought about running Evan's this year but with this new coolant system I can't see it ever getting hot enough to boil. One thing worth mentioning is that with this type of setup it's tough to get all of the air out of the system so the first ride out I carried a 1.5l bottle of coolant with me and topped the coolant bottle off twice throughout the day before I finally got all the air out.