My work experience in industrial equipment usually had requirements for products like oils and additives to be limited to be manufacture approved. Therefore, I'm biased that way in my personal vehicles and equipment. I have been using Stanadyne in every tank for 10 years in my PDS 6.0 for the benefits to the motor however, I assume there are benefits to my Esbar D4 as well. I originally chose Stanadyne because it is formulated by the manufacturer of injectors and fuel delivery equipment. Probably have several thousand hours of run time on my heater and the only thing I've ever done to the Esbar is change the catalyst screen last year. I've never had the heater not start or flame out in 10 years even with fuel and air temps near zero F while starting. If I had a Sprinter I would just check to make sure Stanadyne wasn't prohibited to use, I would be surprised if it was, and continue to use it based on my experience with the heater, and engine. Here are some links for Stanadyne.
I purchase it by the case from here but it's also available at the chain parts stores.
Here is some more info.
I don't find many folks using or endorsing Stanadyne as it doesn't seem to have the energy drink style marketing of other additives.