Stayed here recently to check out the property. The hotel rooms are only on floors 11, 12, 14, and 15.

PROS:
Great location!
Beautiful rooms (better than most Hiltons)
King-size beds
Great lounge breakfast (thick cut bacon, chicken apple sausage, custom omelettes)
** unclear if omelettes are complimentary- ask executive lounge staff
Lounge has Acqua Panna
Rooms have 65" TVs
Rooms have many power outlets
Great water pressure and temperature
Bathroom has permanent night light mounted under the mirror

CONS:
So-so evening lounge presentation
Road noise from 395
Few suites means no chance of room upgrade as elite
Poorly conceived shower design; the shower head should be on opposite wall from controls and stall entrance to minimize splashing
Motion control bathroom lights kept turning off
Poor fitness center
Pool perpetually under construction
Lobby a little too minimalist, needs more chairs/sofas for lounging
Executive lounge lacks natural light

It's a solid property, and better than the Capital Hilton. Having stayed at various Marriott/Hilton hotels with lounges in the DC area, I'd rank them as such:

1) Conrad DC
2) Crystal Gateway Marriott
3) Hilton National Mall
4) Georgetown Marriott
5) Ritz Tysons
6) Marriott North Bethesda