I have yet to hear a single person say that Marriott status gives better perks than Hyatt Diamond. So why spend 50-75 nights in 2015 trying to retain such status when you could spend them at a Hyatt.

The analysis changes when:

1. you tend to visit places where there aren't Hyatts in your price range - therefore you need a secondary status
2. your typical Hyatt stays are at Hyatt Place, Hyatt House, Hyatts without a Club lounge, etc. where there's less benefit to being Diamond

Personally I think HHonors Gold works as a better back-up option and you can get that from a credit card.