I like the Galleria hotel a lot. I get treated well there. Early on, I always got an upgrade to a suite at check-in, but of late, that is getting more rare (as I think their overall occupancy is up). It is certainly newer and will feel more updated than downtown.

I prefer having the lounge over the breakfast buffet (I'm in a minority on this one) because I like access to soda/water/snacks all day (they have cookies the size of your head).

The big question for me is what are you planning to do in Houston and what part of town will you be doing activities? Traffic is bad in the Galleria, but getting in and out of downtown traffic is more of a pain in my opinion. Depending on where you are going, you could conceivably fight downtown and Galleria traffic on the same trip.

The museum district/zoo is not difficult to get to from the Galleria, but it is an even easier quick train ride from downtown. NASA is far away from both. There are many, many more restaurant choices near the Galleria (and the big mall if you like that kind of thing).