I've had good experience with Marathon series and haven't minded the extra weight. Cycled across Russia, starting with a pair of Marathon Plus. Front tire went entire distance (~8000 miles from Amsterdam to Vladivostok), rear tire was replaced half way across with a Marathon XR I had with me. One flat in that distance, which happened just before I replaced the tire (had a slow leak, couldn't easily find it with road noise so replaced tube and tire since tire was also fairly worn).

Also cycled across Africa with Marathon Dureme/Marathon Plus combination. Had ~3 flats in that distance with a fair amount of thorns in parts of the route. Among other riders also on that TDA ride, there were some with up to 50 flats. Sometimes due to special situations with rims but also sometimes having not quite puncture resistant tires in some of the off-pavement sections. There were some other tires that seemed to do ok, but Marathon series definitely above average.