When my previous pair of goggles were about to give up the ghost I decided to treat myself and pick up a pair of these. They look awesome and I had high hopes, but unfortunately when they arrived I found them to be easily the most uncomfortable goggles I've ever tried. I couldn't keep them on my face for more than a couple of minutes before they became too painful to deal with, so I had to send them back for a refund. The problems I encountered were:
1. There's plenty of adjustment in the strap, except for if you have a big head. You could feasibly adjust these down so small that they'd fit the head of a new-born baby, but when adjusting them the other way the strap just isn't long enough for big heads. My head isn't massive but it's probably a little bigger than average (I'm 6'2), and even with the strap adjusted as big as possible it felt like it was trying to pull the goggles through my face. Not good.
2. As can be seen in the pictures, there's a little 'arm' of plastic on either side of the goggle that the strap fits into. These arms are made of hard, sharp-edged plastic and they jabbed into my temples whenever I put the goggles on. Again, this might be due to having a larger head.
3. All the nose bridges supplied are virtually flat, rather than being curved (as the bridge of one's nose is, funnily enough.). This resulted in the nose bridge being jammed uncomfortably into my nose all the time.
If you're a swimmer of the larger-headed persuasion, you might want to do what I did and buy a pair of Aqua Sphere Kayenne goggles instead. They're a comfy fit, the push-button adjustment system is simplicity itself and they have masses of room on the strap to fit your melon in!