Our Giant expedition touring bikes came fitted with Vredestein Spider tyres. These did nearly 4000 miles with heavy loads on very mixed riding conditions from tarmac to the gravel roads in Finland, they also performed reasonably well off road in Norway. They were superb, they rolled well on normal roads and the nobly side bits helped in the gravel. Their puncture resistance was brilliant, my wife had no punctures in her 4000 miles and I had only one and that was because I rode along a verge to get some respite from the jolts of a cobbled road in Poland and picked up a thorn in the top side wall.
Due to their success we purchased a second set of Spider Max tyres prior to our trip in 2005. Unfortunately we haven't found these so good and after 600 miles they have started to show signs of the side walls splitting slightly. On our recent tour to Norway my rear tyre started to bulge slightly in one place and to be on the safe side I replaced it with a Spectra Ruby.
Whether the tyres were a duff batch I don't know, but we were slightly disappointing after their previous performance. We replace them with Schwalbe Marathons XR's for our tour in Iceland and they were excellent.