Somehow - I've ended up with one of each of the bodies you mention.
The MX, in a cock-eyed way of looking at things, is a mix of the other two bodies you have. Nice and compact like the ME Super, but with more the robust, almost clunky mechanical feel of the K1000 - but somehow 'smoother'. I don't think an MX will 'give' you anything that you haven't got already in a technical sense (someone will correct this statemenet shortly
), but the MX is is a very nice tool to use.
I am not heavy user of my film cameras, but when the time comes to take some photos, I always seem to end up loading film in to the MX. The ME Super gets a roll every now and again, but seldom does the K1000 get use.
Going off topic, I've just loaded a roll in to a P30T - I know it's plasticky with an electronic shutter, but it feels nice to hold and use - rotary speed / mode dial which you can use with one finger (try that on an MX - I struggle), it feels light, has a very small but very effective moulded grip and the rubberry take up spool loads film easier than the old magic-needles too (I'm very clumsy). I think I'm going to like using this - much more modern feeling than the other bodies