Ortofon Kadenza Blue or Shelter 501

Hi recently got a P9 now need a cart. phono is AR PH3 SE.

How does a Kadenza Blue sound compared to a Shelter 501?
Dealer says I have enough gain but I'm not sure 54db is enough for a .5 mv cart.

What are my other options?

Thanks Rob
Both are good carts. As for "enough gain", try this calculator: http://www.kabusa.com/pregain.htm