i use level line more often than any other line.for one thing i get it cheap,sometimes $6 brand new.
it roll casts very well,much better than WF for me,and about the same as DT.i do have a silk line that is tapered that roll casts better but that is an exception.
most of the fishing i do requires casts of less than forty feet.so i don't really need a taper for that.
it should be noted that i don't nymph fish as much as i wet fly fish with some streamer and dry fly fishing.