Nice hotel room, good facility, nice breakfast buffet. Friendly staff and there are plenty of them in the lobby. 5 minutes of walk and you are right under the Arch.
My room was at the south-west corner, close to the old court house, at 10+ level. I can always hear the noise due to the traffic (probably from I70), sometimes there were car beeping or motorcycle zooming sound, this makes a bit difficult for sleep at night. I understand the hotel couldn't reduce the traffic, maybe there is some improvement they could do with the windows. One friend of mine stayed in 6th floor and he didn't feel that, so I guess that highly depends on the level and specific room/window you have.