I prefer to run braid to leader on most of my setups because I feel like it gives me the best of everything. I tie an improved alberto knot and never, ever have knot failures there so that is not a concern for me.
The few exceptions to the above for me are as follows:
Topwater - straight mono
Heavy swimbait setup - copoly (Defier Armilo)
Any bait where I am making long casts and trying to keep it as deep as possible, like a spybait or deep crank - flourocarbon
Frogging, jigs not fished around rocky areas, chatterbaits, buzzbaits - straight braid
On the few setups that I do use straight FC, it is Tatsu 100% of the time. Also, none of those are spinning setups.