Buy the best pipe you can afford. Period. Case closed.
Consider buying a quality estate from a company that has refurbished it, and has a good reputation. Some of our sponsors are very good at that. You already mentioned P&C; I have also heard good things about Smokingpipes.com.
If you are not comfy with going that route, I would recommend Stanwell, Peterson, or Savinelli. If you can drop $100-$150, you are gonna get a good quality machine-made briar.
I would not buy a Dr. Grabow. They are not great pipes. MM cobs, while not great, either, are better, IMO, than DG. They may help you build a basic rotation, if you have one good pipe to start with.