Surly decals are a real hit and miss I believe. I have seen posts on MTBR etc that have people complaining that they came straight off. From my experience all of mine were fine and on Heathers old 1X1 that we changed the decals on because they were half rubbed off, the rest of them were a real pain to get off. My frames have always been good with the only one that has shed decals have been the front fork of my LHT, but I think that could be because of computer cable zip tied onto it. I put genuine ones on my Pugsley when I had it repainted and they are so thin I thought they will come off pretty quick, but they seem to have stayed OK and the one on the downtube usually has my PDW mudguard elasticated onto it and it has survived, not that it see's much hard use. If you want non genuine ones, give GilM a shout (on here and at retrodecals on facebook) as he does most of the Surly stuff now. He does all the fatbike stuff and has done my canoe and bikes before, all my 'jamie' decals in the Surly style are donne by Gil.
Jamie