they're quite good, especially in the hiking/trekking world deuter has a good reputation
i used to have a deuter freerider backpack and wore it till the fabric started to discolor and tear....
3y long was it my daily backpack for school, freeriding, climbing, hiking, etc....
so i think it held up pretty well, other packs only lasted 1-2y before zippers started to malfunction or holes began to form ...
but remember, deuter makes a shitload of different packs, its not because one is good that all their packs are....
pick one yourself and look at how its finished around the zippers, seams, closures, etc....