We just returned from a 4 day stay over Christmas from Chicago. We have been there several times for Christmas. We have stayed at the RC, FS, PH, Pen, and WA in the past. This time, we stayed in the Grand Deluxe suite at the Gwen. This was an uprgrade from the Deluxe suite (highest category for online booking). I think the exec suite is the highest. Anyways, it was the largest space of all the hotels we have stayed in Chicago (and that include the lux WA suites). The plus was that the suite was clean and massive (1000+sf) with 2 bathrooms, tvs, sofas, desks in each of the 2 rooms ect. The service, food was also very good. However, like PH, it didn't have the true luxury feel of the WA (our fav). The Pen did feel stiff and I concur with earlier comments on it. The WA was the best so far on all aspects (no issues with any ventilation/air but then we were not using the a-c).
Also, it depends where you want to be situated on the Mag mile. The WA, FS, RC are on the north rim of the mile (more quite, with most of the high end boutiques surrounding them - including Barney's). Pen, PH are slightly further down (next to Saks), Gwen is attached to the Nordstrom and closest to being in the middle of the Mile (across from IC), and, Trump and Langham are further south on the river (Langham, further off the Mile than Trump, as Trump, imo, has the better spot). I have not stayed at either Trump or Langham as yet.