1.75 big bottle on sale for $18. Should I buy it? Any good for mixing or on the rocks?

Also on sale, 750ml bottle Jack Daniels for $19.

I am building a collection that includes WT101, MM, and BT. I'm thinking about adding JD and JB to the bar. Does anyone like JD or JBW? If only one is to be had, which is better- 750ml JD or 1.75L JBW?