My keyword has demand of around 20k. I have a quality score of 10/10. However I'm being told someone has better ad rank so may ad can't be displayed. I can only assume that means someone else has 10/10 and is bidding higher than me. How do I tell what they are bidding? Or can I?
There is no way to know what a competitor's QS is or what they bid. PPC costs are based on supply and demand so yes, you are being basically outbid by others with high quality scores. Download the Adwords FAQ for more details.