Sealskinz socks work well for me on backpacking trips in Snowdonia when I'm continually crossing boggy ground, walking in wet grass, jumping rivulets, following splashy tracks and my boots are absolutely sodden by the end of the first day.
But they are quite expensive for what they are, and they have a relatively short life. The 1st pair I bought leaked during the 6th multple-day trip, the 2nd pair leaked on the 11th trip while the 3rd pair leaked on only the 2nd trip, so the total use of that pair was less than 6 days. I'm currently on my 4th pair which have been OK for 4 trips so far. Leaks seem to start at the toes.
They also let in water easily when your foot goes in water over the top of the sock, after which they never dry out.
They are worth it if you want to have dry tootsies at the end of each day rather than wet socks and wet feet, and for that reason I shall continue to shell out for new ones as and when it becomes necessary.