If you can ride all day long and never think once about yer butt,,, no reason to change.
If not,,,,
So far so good for me too on the stock seat, and actually if anything it has gotten a bit better as it broke in. The true test, like most of us, will come this spring/summer once some trips are planned and taken.
I think next on my list of money I can't avoid spending will be a Madstad.