I've been on Continentals Grand Prix since 1995. There is no better tire for the combination of performance and puncture resistance. Love them. Racing or training, these get well over a season of miles on them (5000).
I put over 3,000 miles on the last Continental Grand Prix 4000S. It is easy to install and the wear indicators provide an idea of how much tread is left on the tire.
I run 28s on both my winter training gravel bike (CX) as well as a tandem. I've ridden on all kinds of gravel roads and even on a few MTB trails with them. On the tandem we've recorded descending speeds of over 60mph and find them totally trustworthy. Logically, they are slightly heavy, but otherwise great handling, super durable, and hard wearing. My go-to tire.