How efficient are pellet stoves vs regular wood stoves, have you ever use it? And what the difference between them? Thanks in advance.

I heard from my friend, that they ever use both wood stove and pellet stove, he told me, the heat of these two types of stove is a little different, he prefer wood stove than a pellet is, you can run the wood stove when you lose power. In fact, I love the smell of the wood and the sight of the logs burning. How about this wood stove,http://www.astove.co.uk/c/wood-burning-stoves