While the Tenderloin is sketchy and often depressing, Phoenix Hotel was a good and affordable place to hang out and rest my head during my business trip to San Francisco. The Internet was free and strong. The employees were gracious and helpful. And the room was spacious.
You do hear other guests but that's more a factor of the glass windows facing the courtyward and the general classic outdoor hallway motel design. But it's minimal and I didn't find it distracting.
It was unusual to check in on a Sunday and have a full blown club turn up in the courtyard complete with thumping bass and flowing booze but it just added to the ambiance of the uniqueness of the hotel.
It's not the most kid-friendly place but the pool is a perk and I did see a number of European families at the hotel.