I've got an MX Sport and when I shredded one of the original equipment Schwalbe Tyragos I replaced it with a Marathon.
That was a hateful tyre - slow, heavy, lacking in grip and it lasted a fortnight before being replaced with a Schwalbe Land Cruiser which is a much better tyre, has a decent level of puncture protection, and has the bonus of them being cheap as chips (almost).
They're fast enough on road for me and have a bit of grip if you fancy some light off roading.