There's not doubt that wolves are very good at what they do, in terms of being predators. I've been fortunate enought o have some lenghty talks to the U.S. Fish and Wildlife guys that do the collaring/tagging in the U.P. and it's pretty fascinating to hear their thoughts on the wolves versus other predators. Bears don't get nearly enough credit for their impact on the fawn crop. Fawns are born the same time bears are leaving their dens, and a bears sense of smell is acute enough to be able to find these fawns, even though they are virtually scent-free after being born. ACcording to them, about 60% of the wolves diet is beaver, especially in spring/summer/fall when the beavers are out and about. They are very slow on land, so the wolves have little trouble catching them. Where the wolves do there most damage (according to these guys) is in the harsh winter months when the deer are yarded up and the snow is deep. The wolves are so much better equipped to run through deep snow, and can therefore track down deer that would normally evade them. They also said that an average pack of 3-4 will average 1 deer per week in the winter, less in the warmer months when there is more easy food around.
As for the coyotes, I know in our area of the UP, since the wolves have become more abundant, we've not seen nor heard from any coyotes.