Update Marriott Munich
I am glad to tell you that the Marriott is finally doing room updates. New interior looks much better than the old one and rooms do get the new flat tv as well. I spend a weekend in one of those rooms recently and will switch most of my stays from the REN to the Marriott next door from now on.
As stated earlier unless one is really into space and therefore is happy about the junior suite upgrade at the REN (90% success as Plat) i would go for the Marriott. Both hotels will grant full buffet breakfast on every day.