I am trying to decide whether to make my own buttercream icing or not. I saw white But-R-Crème made by Dove in the local Cash and Carry store. Any tried this before? Does it crust to the touch or keep soft. Can fondant go over it and not drupe? Hows the flavor?

I have never heard of that, sorry. Scratch always tastes good to me, but my suggestion to you would be pick one up.
I recently saw a container of DH buttercream in our grocery store in the cake isle, along with cream cheese frosting. I couldn't resist picking one of each up, just to see the flavour. Haven't tried the CC but tasted the BC and -wow- very sweet.
Never hutrs to try, right?