These are my favorite climbing shoes, so much so that I have four pairs of them. I have tried the newer Five Ten shoes, but the heel angles backward and creates excess space and discomfort at the back of the shoe. I always order the same size of the Sirens, and only one order was funky. One pair was slightly larger than the other pairs, so there is extra space in the toe box and I am unable to use the front of the shoe. They are comfortable for multipitch climbing as well as gym climbing. Though not very aggressive, I like the fit and rubber on them. Only thing is these shoes reek more than any other climbing shoes. I have tried countless sprays, deodorizers, etc. and have found that the only way to eliminate the stench is by hand washing them, but then it just returns after a few weeks of climbing again. I keep them outside of my climbing bag and in the garage, so I can keep the stink away from the rest of my belongings.