Can someone please give me a rough indicator of the hierarchy system involving Marriott/Ritz Carlton/Starwood?

How can I decide if a Ritz Carlton or St Regis is the premiere brand?
What is the difference between JW Marriott, Westin, W, Le Meridien?
Is Rennaissance better than Sheraton?

I find this whole merger thing too confusing. Does Marriott International even have an idea of what their 'best' brand is?