When I wore Danner Pronghorns I only used Danner waterproofing boot care. Then I had Kenetreks, I only used Kenetrek waterproofing cream. Since the Kenetreks never really fit my feet well, I now have Crispi, and only use Crispi waterproofing cream. I use the same brand of boot treatment as the boots. You have to buy something anyway, why not buy what the manufacturer makes, sells, and recommends?
I wouldn't want to have a warranty issue that the boot maker won't honor because I used the wrong product. I hate to spend $400 on a pair of boots, and try to cut corners on a $20 bottle of boot treatment.
I always treat my boots brand new out of the box before I even take them hunting. I do it again after the season when I clean them and treat them before putting them away.