I do not consider myself to be a Schoeps junkie/fanboy like some people on this board have been rumored to be
, and I don't intend to swap my DPA 4021s for Mk4s anytime soon.
That said, since I have owned my mk41s, I find myself using them more and more. I record in small-to-medium (200-800) clubs mostly, and I find the hypers really cut down on room reflections. Also, just in general, the mk41s sound great--excellent bass response, crisp highs, and none of that nasty tinny-ness that hypers can have. In fact, I still find that even the mk41 can pick up a bit more bass than I like from time to time. Mk4s are a tad too warm/bassy/muddy for my typical uses IMHO, not that I haven't heard many truly outstanding recordings with them.
As Scooter notes, it depends what your primary taping methods are. If you like to be way up front, then cardiods are your better bet. When I do onstage or very near-field recordings I go to my 4021s or even 4061s, and obviously the mk4 is an excellent cap under those conditions also.
I generally try to not be in the way of the audience, which puts me at the back of the room or on a balcony. From those positions, I find more often than not that the mk41 is the way to go.