I've had MKs on my new bike for the last few months or so – they came with the bike. I'm not sure which compound but they are kevlar beads. I normally swap new bike tyres for better ones pretty much straight away, but these worked pretty well. They've been used locally, at trail centres, the Torchbearer solo at 24/12 etc. They get more grip than you'd expect by looking at the tread pattern and are pretty fast running with it.
However, I've had about 10 punctures in that time as well – I can't remember a period of time when I've bought so many puncture repair kits. A couple of those flats were from pinch punctures, but the majority were from thorns.
Basically, grip isn't an issue but show it a thorn, it'll go flat. They've both been replaced with Panaracers but only because of the puncture problem.