Imperial for me. I have 3 sets of Hornady dies, I like the tapered expander ball but the love stops there. I have come to greatly appreciate Forster, Lyman and Redding dies over all the rest.
A die adjustment tip - lube a case and run it up into your die before you lock the die down to the press. This allows for axial alignment of the shell holder, case, and die. Also, brush out the inside of the case neck to get rid of the crud. A good brushing will eliminate having to lube the inside of the case neck. I don't like a "wet" lube on the inside of the neck and will sometimes use powdered graphite poured over #9 shot in a small container as the lube.
In case you're wondering, I use the flat side of the vibrating arm on electric tooth brush to settle powder when doing compressed loads. I run it up and down the side of the case.