Andy,
The best I have ever ridden on IMO.
These are 1.35 " slicks pumped to 4.5 bar but they can go to 6.5 bar if your rims can take it.
V. Light, V.comfortable, V. Fast - I would argue they feel as quick as skinny road tires, but with a little more padding. They are even as light as some much smaller road tires.
I rode the wettest 80 miles I have ever done last year (6 hours in constant downpour) and they always felt planted and tracked.
1000 + road miles with just two punctures ! ( Damn it! I should not have said that! There goes the next day out!) , cant comment on tracks or off road, but I don't think they are really intended for that use for any period.
I personally will not change these now and have even fitted the bike with narrower mudguards !
Let me know if you decide to do it.
Will