We just got back from 4 nights at the Renaissance in Munich and saw the new under-construction Courtyard and Residence Inn while taking the S8 train to the airport. The hotels were on the far side of the tracks when the train went above ground at the Ostbahnhof and I'd surmise that it wouldn't be as convenient to get to the touristy parts of the city center from the new locations (the Ren had a U-Bahn station within a 2 minute walk and was 6 stops/~12 minutes from Marienplatz).
As an aside, the Ren is as terribly out of date as the other threads have said, and no A/C, even on a cool spring day, is awful.