I am considering Alta and Tia Pol's back room for a birthday dinner for 12-15 people in March. I've been to Alta with a group of 6 and we had a wonderful time. I have not eaten at Tia Pol.
I like the idea of the private room, however, the energy at Alta (and the food) is great. Any suggestions/recs would be great especially if you have been to an event at Tia Pol.