Quick and easy service, I wasn't sure about it in the first place but those guys kept what they had promised.
We had two "self players" in the group, me and another guy, both dps. They told us what to do (e.g. you cannot bomb here) in terms of their specific strategy and everything we had to watch for (e.g. deadly boss abilities). So as long as you can play your character, it doesn't matter if you have no experience in the dungeons themselves.
Otherwise you can let them pilot your character, which is also cheaper than playing it yourself. But I would highly recommend to play it for yourself, at least in the first place.
If you want to see them in action, just check out their stream!