I would get a dog that had proven treeing parents on both side of the blood line if your going to get a pup and work it all the way. Or buy a fully finished dog and buy it in the woods after you see what it can do.
I'm kinda partial to original Mountain Curs ...but a lot of good treeing feist too. I think the little fiest may actually be the better squirrelers but I like the versatility of the Mountain cur and I like a little bigger dog.