Love these shoes! I usually buy the Brooks GTS series and have worn them for years. I decided to switch it up a bit after trying on my twin sisters Ghosts. They fit like a dream. I wear a 12AA and these fit not only in the main part of my foot, but also in the heel where I am a 12AAAA. They are perfectly comfortable as is and for a little more support, because I have very flat feet, I added an insole I got at my local running store.