Solid hotel, nothing spectacular
Have stayed multiple times at both the Westin Oaks and Westin Galleria, and they are virtually twins of each other. Good Westin experience at both, with comfortable bedding. A pet peeve of mine is that neither the Galleria nor the Oaks have plug ins available near the nightstands. This is a little thing but noticeable to me.
The hotel was quiet. No restaurant in the normal hotel sense, but they have a deal with the Daily Grill just inside the mall area that allows direct room charges--and that is an excellent substitute for typical hotel diners!
If you need to be at or near the Galleria Mall or Williams Tower, this hotel is fine. Just don't expect a higher-end Westin.