I started using a pair of 5.10 Mesas for trad climbing this year. I bought them comfy and at first I loved them, but pretty soon the stench became unbearable. I've ditched them for some Sportiva Barracudas that have bagged out slightly after a winter season of bouldering - these don't smell at all.
My mate Rob used to climb in a pair of Newtons and if he was seconding a pitch, I swear I could smell him getting close (i.e. 50 feet away!), especially on a hot day.