This is my first experience with Icebreaker socks and I am highly impressed. I used to think that Smartwool was the only good merino option, but these were on sale so I figured I'd give them a try. The features, quality construction, and attention to detail of these socks is just as good as anything Smartwool makes.
And since I've been comparing these to Smartwool, I think it's important to note the differences between these and the Smartwool midweight hiking socks. I have both, and the Icebreakers are quite a bit lighter. Nothing wrong with that, just be aware of this fact if you are choosing between the two. I bought the silver/red/oil color and was surprised to find out that they are a lot more grey than the backcountry.com picture would indicate.
I'm quite happy with this purchase and will probably be buying more of these in the near future.