To update this thread with new data points:
I've stayed here on past visits to Portland and enjoyed it but I've since moved here. We decided to take a brief weekend staycation and found this to be a great opportunity to book through FHR and use the Amex Plat credit. The benefits are similar to what jamesl posted above but the breakfast credit is now $30 per person instead of $33 that very specifically does not stack with either the $100 amenity credit or the elite breakfast credit.

We got upgraded from our booked "Corner Room" (at $179/night plus tax) to a top-floor "Premier Room". I think just about all the non-suite rooms are the same and they only separate the categories by floor. Everything is clean and functional and will probably be due for a refresh in a few more years.

Food at Mayrose was great, service was friendly but incredibly harried; they seemed understaffed, with a 20-30 minute wait for a table for breakfast even as the restaurant was less than half full.

The FHR benefits letter also included a promotion code for premium wifi; I tested it at 30 megabits, which is fine I guess but an order of magnitude slower than what it should be at this point.

Generally it feels like they're trying but not quite succeeding at bridging the gap between a premium hotel and a luxury hotel, and everything seems like after a couple years of COVID survival mode it's not as nice as it used to be. Inclusion in FHR at all suggests that they're trying but beyond the really beautiful decor, everything else about this hotel is the same as a standard Hilton. That makes sense given the common property ownership and management with the standard Hilton across the street!