I built half of my cellar from P&C. Had one problem and they handled it well enough.
They are the walmart of our world. They are usually cheapest and that comes with a cost, lesser service. If you want lightning fast shipping and pretty boxes, shop elsewhere. If you don't care how long the order takes and if the shipping carton is crushed, then proceed.
To address the site sponsor issue, they WERE a sponsor, but pulled out after experiencing weekly dog-pile bashing threads here. I don't blame them.
Their backorder system IS jacked up. If you pay with paypal and an item is unavailable or delayed, you order will fall into some sort of black hole that no one there seems to be able to figure out.