My DH has 2 pairs of SIDIs - road and mtb. The road shoes are at least 6 years old - the mtb's are 4. He's worn them through tropical storms (7" of rain - boy did EVERYthing get wet!) and all sorts of weather. I've never heard him say anything negative about the shoes. In fact, that is all he'll wear when it comes to bike shoes.
p.s. My only negative comment about SIDIs would be the women's shoes don't come in my size!