This hotel is beautiful! I have stayed here many many times and never had a bad experience. I'm from San Luis originally but live in the states and every time I visit I stay here.
The breakfast buffet is the best in town. The service is amazing... Everyone on staff is helpful.
The only bad thing is that sometimes they use the courtyard for wedding receptions and it may get loud, so when you make the trip make sure there's no party Saturday night or you don't mind a little noise until midnight.

Stayed on a Saturday night and on the weekends the ballroom is apparently a night club which isn't a problem but the people talking in the pool area until 5AM after the club closed was a problem. Room service took one hour to arrive. Checkout took 25 minutes as there's only two people seated at desks attending to the whole hotel.

The hotel and rooms are beautifully decorated and luxurious. A couple of us complained the rooms were dark though and a little scary. The two restaurants on site were very good. (I did not try the worms or the grasshoppers on the menu - no kidding. They are some Mexican delicacy but I declined.) The breakfast buffet was particularly generous, many choices and very good. The rooms surround a large open space. Since I stayed in December this area was used for large (several hundred people) and VERY loud holiday parties. The management courteously left a memo under our doors to be aware that these parties were going to take place and as late as 3am, and were handing out ear plugs for hotel guests. (I tried them but they did nothing to block the noise.) So all in all it is a beautifully appointed hotel, as the summary states - elegant but can be really noisy . The last note, they have a shuttle to and from the airport, but on my departure the van was broken down. With some negotiating the desk staff agreed to provide a taxi ride in lieu of the van, and that was fair and appreciated.

We were traveling with our dog required a pet-friendly hotel. We contacted by email the Westin to confirm that we could bring our pet and received, promptly, a confirming email that they would be waiting for us and our dog when we arrived. When I walked into the lobby, I couldn't believe that we had booked into such a welcoming and beautiful facility. The courtyard is stunning, the rooms extremely beautiful and opulent and the food at the restaurant well presented and well priced. In the morning, we enjoyed a full breakfast before we started back on the road. This hotel was such a treat, I tell people that they should visit San Luis Potosi just to stay one night in the Westin. A real tribute to the chain.