They must have sold at least one pair Mr Biggs 'cause I'm friends with a lady who uses them. I bumped into her, not literally, on a local cycle track about a month ago as she was trying them for the first time. After only a few miles she wasn't ready to give her verdict on their characteristics although she did say the shop took two hours to fit them. But hey, every new technology takes a while to bed-in.
I tested and reviewed a set for Wheelsuckers some time ago.
If you're after tyres for your London commuter fixie then they'd be a pretty safe bet. Or even for your winter hack they'd do a good enough job.
They lacked any supple feel or finesse. For a high mileage fast road bike? Forget it. And yes they take an age (and a lot of muscle) to fit properly and even harder to get off - unless you use a hacksaw - deadly serious! They have their place, but certainly not my cup of tea...