I've never tasted Mrs Fields before. So my choice would be
Famous Amos!! 
However, I strongly encourage all cookie lovers out there to bake
their own cookies.
Firstly, cookies taste wonderful straight from the oven!
Secondly, it is possible to make cookies that taste similar to
Famous Amos cookies. I have a couple of recipes that bring out
cookies tastier than commercially sold cookies.
Thirdly, you can always make changes to the recipes to suit your
preferences. Like, cookies that aren't too sweet, cookies that are
healthier, cookies containing your favorite nuts or chocolates like
M&M's!
It isn't that hard to bake cookies. Quite fun actually, like
playing with Play-Doh. 
