Definitely tour all the facilities you would frequent to see amenities first-hand. Which facility is "better" for you will depend on what you want to do at the gym.
Aerofit generally has more variety in the amenities it offers - it's not just a "gym" but more of a health club type facility.
For example, here is a list of amenities that I think Aerofit has that Gold's does not:
Racquetball courts
Tennis courts
Hot tubs
Indoor heated pool (Villa Maria location)
Outdoor pools (Carter Creek location)
Indoor basketball court (Villa Maria location)
If you won't use the above amenities (e.g. you only use cardio studio equipment and weights/machines) then Gold's gym generally has nicer everything in those departments.
As far as membership costs, be careful when comparing the two. I recall Aerofit is a pure monthly fee (i.e. 12 payments per year), while Gold's was bi-weekly or something (i.e. 26 payments per year) and NOT two payments per month. You can't just double the Gold's payment to get a monthly equivalent for comparison.
Also, Aerofit charges a "facility enhancement fee" once a year. I don't recall the amount and I don't know if Gold's does something similar. All this said, both places had similar fees when I compared a year ago.
Locations: It sounds like you are not interested in South College Station locations based on your comment regarding the Dome, but Aerofit is adding a location at the College Station Med and also has two of those 24-hour locations - one by Target in Bryan off the bypass and the other in College Station on Wellborn Rd.