Concierge level is nice but honestly I've really used it maybe 10% of the time. The bonus at Black, and even more at Platinum, does add up. I'm still amazed I'm going to beat half a _million_ Marriott Rewards points in less than a year, with everything except about 50k coming from hotel stays (most coming from promotions, some from Hertz, a few from AT&T).

Treatment is marginally better too. If you plan to stay at Marriott's next year, I'd suggest go for black and try to get comped. Maybe your airline of choice has affiliation with some hotel? I made Hilton Gold due to USAirways..