Ha, I think WPRESTO is giving some good advice--at your price point, I don't think you'll find any dogs, and will quickly adapt to whatever your choice happens to be. As for the P0, I don't own one yet (and I would be very happy with any Acratech head)--it was on my radar because I'm looking for a light, capable option for my "backcountry" kit. (Right now, I run a Manfrotto 410 geared head, which is great for landscapes and macros, but a bit heavy to get the top of the hill at my age.)
FWIW, here's a Ming Thein review of the P0:
https://blog.mingthein.com/2013/08/20/review-arca-swiss-p0-monoball/