Buck is definitely the mule team of knives, hard working, somewhat plain, sturdy. Case is more the Quarterhorse type, still capable of hard work but much fancier. I have owned both and have always been happy with both. Case does make the plain knives as well and if you compare Buck to Delrin handled Case knives I think it is a draw for the most part. I think were Buck shines most is in the fixed blade arena, they have made some of the best production hunting knives out there.
Lock Backs are another Buck strength with one exception, the older Case Sharktooth. I have owned a couple of Buck 110s and didn't know what I was missing till I handled a Sharktooth. Suddenly instead of a square slab my hand was holding a nicely rounded and contoured knife. It simply fit in my hand better, the round grip is more comfortable as well. The bolster swell just enough to provide the thumb a place to have a bit of leverage. In the large lock backs I have to give the nod to Case but in the smaller lock backs it is all Buck.