I think the earning potential is higher at Marriott (10 pts per $ + elite bonus + 3 pts per $ with the Marriott Visa card).
As Hawkeye noted above, the redemption with Marriott is much better - i.e less points needed for free nights.
Marriott's all inclusive awards can't be beat, IMO. Their 200,000 pt award is awesome.
I have always been upgraded to the concierge level. However, the rooms seem to be the same as the non concierge floors with the exception of the free bottles of water.