In reply to t__her6:
I like the Speedcross 3s. I find the grip very good. You have to assess the ground as you run. You can slip and trip with the most aggressive studded shoes if you don't. I wouldn't use them for all out racing downhill but for everything else yes, including tarmac.
They are very comfortable though the padding means they are rather hot in summer. Beware not tucking the laces in properly, they can catch on heather or branches and snap.
It's a pity the sole wears quickly. Also if you get the shoe soaked running through streams and swamps the rather weak insoles can wrinkle on descent, which is very annoying.
I don't believe they are any worse than any other shoe on wet rock. Wet rock varies in its slipperyness. Some is like ice, some grippy. I avoid it!
If you are running mostly on gravel I would try and find a shoe with a sole more resistant to wear.