If I recall the fisher anvils were cast iron bodies with a tool steel face. I would place them between a cast iron anvil (a paperweight, anchor, or doorstop as far as I am concerned) and a traditional wrought iron/tool steel faced anvil (Peter Wright, Trenton, Mousehole). they were a popular anvil as they could be made cheaper than a traditional anvil, but had problems with the horns breaking, and sometimes the heel breaking. under heavy stresses some of them lost their face entirely.
That being said, if you are using the anvil for bladesmithing, the horn isn't that important, and if you don't work with a hammer over 7 lbs you should have no worries about the heel or the face other than minor chipping at the edges, but that can happen on any anvil. which is a good reason to round the edges, the other being not having a sharp mark on the bottom of your work that could then be hammered into a crease or cold shut.
he fisher anvils were also known for their sound, it isn't a ring like a traditional anvil, but more of a whunk sound, and a bit quieter.
$2-$3/lb is a good range to pay for an anvil in good condition. Heck, if I didn't already have several anvils, I might grab that.