I've stayed at both the HR (newer West tower only) and the PH using FFNs from two years ago. The HR is much more of a convention hotel, located closer to, virtually next to, the Loop (and thus, museums, Grant Park, etc), but in my opinion, doesn't come close to the PH, which is better located for well... most things, in terms of experience. The PH has something like 10 rooms per floor arranged in a square fashion around the elevator banks, if I remember correctly.

Haven't tried the Blu yet, but that building is pretty spanking new, so I'd consider that a viable option as well, especially considering the decent price point (or maybe not.. I'm a tad jaded having just come back from Sydney hotel rates) compared to the PH.