Oh, I really love mine. I just have a super-basic Brother machine and found one for my model on Amazon. Now I don't know how I did without it and my 1/4" piecing foot!
My walking foot is pretty easy to attach. It does have it's own screw that is longer than the one I use for my other feet.I need a system for storing my feet when I switch them out so I don't lose a piece!
I don't know of a con!