IMHO I think you will find that most every reputable shop, Beaver Sales - Hendersons, etc., will turn to KONI shocks as the best on the market today for an RV of the Beaver caliber. Yes they are pricey but they do return for that price the best handling and ride possible for many thousands of miles on a 30,000 - 50,000 lb unit
I believe it was Safari or Monaco that shifted Beaver from Koni to others as they probably saved $ where most buyers never looked or knew what to look for. Gerald would know if Beaver ever used other than Koni's.
In my experience if you ever hold any other shock next to a KONI you will know they are going to be different. We have been asking KONI for years to make one for the F-250/350 series as we have tried everything including Bilstiens and none hold up more than 15000 miles or give the handling of a KONI. The feel good new is not the true test.