I loved the Conti 4000s, also. DH went and bought some other ones for my Kuota, though... so far, so good. I have had hardly any flats in 11 years, most of them being last year on my tour, when the roads in NY state were just full of glass.
I have the Gatorskins on my Guru. I hope I never get a flat, as I've heard they are awful to take off.