These are very comfy! I get lots of compliments about them at work. My shoes tend to dig in to the back of my heel and cause pain, but with these socks, I didn't notice anything after a full night! They are also more slippery than cotton socks. They are ideal for going dancing in, as I didn't notice any problems with friction or hot spots I usually get with cotton socks, they hold onto your feet well.
The design gets distorted and stretched out a lot when wearing them, and the base color can show through on the design. If you really care about a clean look, these might not be the best for you. They're still really cute though.
I dislike the feeling of tight socks. If you do too, then get a size up and wash/dry them at medium heat (and repeat) until they fit just right, then line dry from then on.