These tyres are a must for those who don't spend all their time riding off road in mud or on very rough surfaces. If you mainly ride on roads, tracks or canal paths, you really should get a pair of these. The difference they make on road is really incredible - if you are used to knobbly tyres you won't believe the transformation they make until you try! I used to have some semi-slicks on my bike before these, which were an incredible improvement over the knobbly tyres it came with. But these are even better!
They inflate to 85 psi, which means rolling resistance is minimised. Only the central 20mm or so of the tyre makes contact with the road, the remainder of the tyre 'air cushion' is used to absorb shock. Their responsiveness - particularly their ability to very quickly steer around potholes - is remarkable. The ride will obviously feel hard if you are used to low pressure off-road tyres, but it's a worthwhile trade-off. I never use my lower gears since getting these, as I can maintain greater velocity so much easier. 17mph is quite an easy speed to maintain on a smooth level road, and I'm only a 'fair weather' cyclist on a pretty modest old bike. Trust me, your MTB will fly.
They grip well, and very importantly offer puncture resistance. I would never go back to tyres without this feature now.
I haven't had mine for long enough to comment on durability, but by all accounts they last very well and I have no reason to doubt this. The price is reasonable in any case, and I will be seeking out some more when the time comes.
I wish everyone knew just how much better their MTB would ride on hard surfaces on these tyres! Get a pair.