X3e is VERY stable.
I do not believe staff view has gotten any particular development attention in a good many years, to the best of my knowledge (I dimly recall some changes, but most folks appear to have written it off).
I think folks who are serious about notation are using 3rd-party notation programs, such as Finale. There are others, but I don't recall what they are, off the top of my head.
But, the main functionality of X3e has been incredibly stable for just about everybody, and there are no show stoppers that come to mind.
Bob Bone