Nishiki TriA with 700x25 Conti GP4000SII - I tried to fit a 28 but it will rub the frame.
Centurion Pro Tour 15 with 700x28 GP4000SII.
4 flat experience on both with 10k plus miles - the path/roads I drive are pretty nice to ride.
I got two flats when I went for a 140 mile loop Seattle, Tacoma, Olympic Peninsula, Mukilteo this past Fall.
Got the GP5000s but didn't have chance to install them yet.