Saddle has a lot to do with it; back in my rando days I was doing 600k's with no chamois cream at all - that was on a Brooks b17 saddle.
Now, racing on a "race" saddle that is much smaller, I use butt'r when rides get above 4-5 hours.
As for the butt'r types, they all seem the same to me; my guess is that the differences are all in marketing.