We know that they are not as powerful or as wise as the high Elves of the West. In The Hobbit (book) the wood-elves put a spell on Thorin when they capture him.
"Consequently Thorin was angry at their treatment of him, when they took their spell off him and he came to his senses" (from the chapter "Flies and Spiders").
Then the Elvenking talks about the magic of his elven gates or rather the magic on them.
"There is no escape from my magic doors for those who are once brought inside" (from the chapter "Barrels out of Bond").
So, while being lesser Elves than the Noldor, how much power did Thranduil, a Sindarin Elf, and the silvan Elves possess?