Stay this weekend for a work meeting on site.
1) Entrance/Check-in: The lobby is stunning as you enter. I love these conversions in building with prior functions. My first experiences with this were the Ritz-Carlton and the Loews in Philadelphia. This is no exception. It appears to be most walnut paneling with brushed nickel/steel finishing. However, there is slight confusion as you enter the main entrance. Despite two door men sitting there, no greeting or offer to assist. There is poor signage for the check-in desk [As you enter, veer directly right and then BEHIND the lobby bar, which takes most of the space]. At check-in, two agents were present, and one handled some matter with the staff before he took care of me . Gold status recognized, and after that no concerns.
2) Room. Starwood floor was floor 7. No real Upgrade to speak of. 2pm checkout provided. Consistent with the conversion, the rooms are small. These were most likely carved out of prior offices. Bathrooms are VERY tiny. They would have been better served to have sliding doors to conserve some space. No real counter space to consider. Shower (only) is dual-head heavenly type. Good water pressure and temperature. Very brightly lit. Towel bar over the toilet which is a pet peeve. The room itself is small, and they made a poor choice I think in furnishing with king-sized beds. I would have preferred a queen and slightly more space. Flat screen TV (with high definition channels IIRC), wired/wifi internet for $11.95. Quirky alarm clock that has no instructions. Heavenly bed was pleasant. Mini-bar and complimentary bottle of water for SPG elites. Colleagues complained they heard a lot of noise overnight from the hallways, but I heard nothing. So perhaps there is a problem with insulation. Key access to rooms and floors is annoying.
3) Amenities. Bar is spectacular. Stainless steel swimming pool is their novelty act, but it's pleasant if not small. There is also a whirlpool. Gym is slightly above-average, with ~ 5 treadmills, 2 bikes, 2 stairmasters, and 1 elliptical with TV access. Reebok balls, and such are available. Two benches, some weights, and one multi-function machine.
4) Location. Downtown (close to the bridge accident). Some shopping areas reported nearby, but I did not have time. A colleague took the train to the mall of America and reported a 15 minute ride there, with a longer ride back.
5) Misc. Our meeting was in-house. Catering menu was creative, tasty, and nicely presented, however, they seemed slow. Our catered breakfast was over 30 minutes late one morning. Staff are uniformly pleasant (the Westin vs. MSP effect?). Wake up calls were late one morning with profuse apologies. Meeting rooms are very well appointed and I would recommend them to you, provided you get some service details fleshed out with them.
Lots of NTSB people staying at the property.

verdict: Definitely an excellent choice if staying in downtown MSP. Outstanding physical plant, if not "cozy." If you don't anticipate unusual needs or lots of staff interaction, I think you'll be fine. Probably not quite ready for prime time.