Steve,
I bought an MX a couple of years ago for the very good reason that it was cheap due to needing an easy fix, which I did. Like you, I used it first when I wasn't going out with the specific intention of taking photos, regarding the KX/K2 for 'proper' photography sessions, but I grew to love it more and more and now find myself using it as my primary 35mm SLR. I don't have any problems with the controls and I've got hands like bunches of bananas. My only complaint is that the LEDs are hard to see in bright light conditions - I went on a sea trip last weekend and was really struggling. If it had a Spotmatic style match needle system, I'd be much happier. The MX plus 40mm pancake is a great combination!
Cheers,
Steve