[embee]

When working for a major vehicle manufacturer about 25yrs ago I dd some work with a supplier wanting to sell us propylene glycol coolant with all the claims you hear now. We did various tests.
Bottom line is that "conventional" ethylene glycol based coolants do the job and are still used by all (as far as I know) main vehicle manufacturers.
Coolant does a number of jobs. It carries heat away from the hot bits, it needs to avoid freezing, and it needs to provide corrosion inhibitors.
FWIW my recommendation is to use an ethylene glycol based coolant from a well known manufacturer, either a vehicle branded product or a reputable supplier of such products. One of the significant aspects is whether it is silicate free if the vehicle manufacturer stipulates this. There are other additives which may or may not be acceptable or desirable (borates etc).
Having looked into generally suitable coolants for my fleet of engines, I use Comma G30 in most things (not all), it is based on BASF Glysantin30 and is silicate free (BASF are one of the biggest manufacturers of this type of product). You can check the data sheets on most supplier websites. Some vehicles have quite specific requirements for various reasons, many are happy with generic type coolants.
Changing coolant in a bike every 5yrs or so isn't a big deal IMO.
(I have no connection with Comma nor BASF nor any other commercial producer).