There are several reasons I don't agree with allowing dogs to sleep with their owners though I did it for years. Breaking them of the habit was one of the smartest things I ever did. For us and the dogs!

The first and most obvious is that it's messy and itchy. Washing sheets every day and clogging the washer and dryer with gobs of dog hair isn't my idea of a good time.

Big dogs take up too much space, don't care if they're laying on your feet and you can't move; put out too much body heat in the summer (their body temperature is 4 points higher than ours) and they lay on the covers in winter--usually during the coldest part of the night! Sometimes they snore too!

A dog needs a place that it can call it's own and doesn't have to share with anyone!

Sleeping with the owners can also cause seperation anxiety.

I'll let someone else get into the dominance problems that can develop. Though I'm aware of them I've never experienced them personally, but that could have been dumb luck!