Looking to add efficiency for my wood burning fireplace... Has anyone used one of those fireplace fans/tube systems added to their fireplace? Do they work? Do you recommend a particular brand?

Wood burning fireplaces are one of the most inefficient items you can try to heat with. I suggest buying a wood stove designed to be used in a fireplace(fireplace insert) before wasting $$ on a blower attachment.

Sic258... to answer your question... yes, they work. Unfortunately they don't have a long life expectancy, but they do as advertised.

I had one for about 15 years in two different fireplaces and it was fantastic. It is still in the house we sold two years ago as far as I know. Ours came through Sears but that was a long time ago.
Missouri is correct, the life expectancy varies. Ours developed a small hole which I was able to patch successfully. I think it was a manufacturing defect. You have to watch them and maintain them because they can blow hot sparks or embers into the room if holes develop.
I have a stupid propane fireplace now. I wish I had my fireplace and blower back.