Noise as they age may be considered a con, but any aggressive tire will have this problem. I've only got a couple thousand miles on mine, but do understand noise comes with age on a tire like this.
Only real con (besides price) is a weak sidewall. They only have a 2 ply sidewall, some prefer a thicker sidewall, especially if you're around a lot of sharp rocks. I've read a lot of handling complaints from people with larger/heavier vehicles, but those issues don't seem to affect the 4runer owners.