I bought a pair of these tyres recently, and I've now had the chance to road test them on two day rides.
First of all, I approached the fitting with trepidation having read some of the reviews on other sites. But, armed with the highly recommended YouTube video by Spa Cycles which explains how to fit them without using levers, I had them on easily within 20 minutes or so. As I'm one of the least practical people on the planet, that's good going! The "trick" is to secure the tyre using toe-clips, string or cable-ties, then gradually work round the tyre, creating slack by "bedding" the tyre in the rim well, making sure the inner isn't snagged. It's much easier to watch than explain, but if I can do it, believe me it can't be that bad. I guess that the wheel rim type will make a difference to how easy the fitting process is; mine are Mavik 319s. Anyway, I'm now confident that I could fix a puncture on the road if I need to. Not bad for a numpty like me.
The ride seems fine. I don't detect any appreciable slowing effect over my previous tyres from the extra puncture protection. I'm using them on a loaded touring bike (20kg spread over 4 panniers).
I'm about to embark on a lengthy tour (4000+ miles) with these tyres, so will report back more fully on how they perform. But for now, it's thumbs up.
Update: I've now completed 2500 miles using these tyres and I've found them to be remarkably durable. Firstly, I've had no punctures, despite riding over diverse surfaces including rough chalk, potholed lanes, and broken-glass on city cycle paths. I ran over a thorn, which I removed from the tyre with no problem at all. The wear seems light, and I like the light-reflective band on the tyre edge.
I'd recommend thes to any touring or commuter cyclist who is fed up of getting punctures.
So, only a partial review, but I thought it might be useful for anyone who is put off by the fitting issues.