I recently bought a Bernina and spent the extra money for the walking foot and I absolutely love, love it!! I pull it out for everything.... I use it for any project over 2 layers or anything that I just can't get to lay flat....I would encourage anyone who doesn't have one to at least try it...
There are some low cost ones out there that just screw on to any machine...they are a pain but made me realize that I needed to invest in a good one esp. for my machine.