my wife and i have just cruised on Coral Princess with 2 other couples. Being from a non tipping country we struggle with the idea of tipping, especially when it is added to the bill! As for the art auctions, we purchased a few lithographs (costing thousands) and I have noticed one in particular advertised via a dealer in the US for around $4k cheaper than we paid without the 15% buyers premium. Others are advertised at a higher price but without the premium they are still cheaper. They did state that delivery can take up to 8 weeks but some of ours have been delivered already and we have only been home for 8 days. Service onboard was overall excellent.