Always a pleasure and a class act
I've stayed many times at the Westin Riverwalk in San Antonio and will do so again. I can always count on a pleasurable experience -- from the service of staff members like Monica Castillo in the convention services department to the front desk staff to the concierge to the wait staff in their wonderful Zocca restaurant. (By the way, this is one of the nicest Italian restaurants in the city, and their weekend brunch is a real treat as well. Casual, classy ambience.)
On this last trip, Wendy at the front desk was friendly and helpful, pointing out that I could sign up for the hotel's rewards program. 
Service and a relaxing first-class experience set the Westin apart. You won't have to worry about noisy, raucous guests in the poor or the bar or lobby. And, of course, it's right on the Riverwalk. On that point, one more thing, you're right on the Riverwalk with a gorgeous restaurant bar and patio right on the river's edge. But you far from the hullabaloo of the River Walk further east and north and its clubs and restaurants. Not that there's anything wrong with that party scene. And if you want to partake in it, it's just a short, delightful stroll away.