My recent stay at the Transamerica Prime International Plaza in Sao Paulo was good overall. Stay was from June 30-July 4, 2014.
The good:
Great location one block away from Avenida Paulista, less expensive compared to many other hotels in this area, a decent clean room at a fair price, great breakfast spread. One positive was the manually controlled fan/AC unit in room that you can leave on High setting to provide continual background noise.
The City View rooftop restaurant and bar was a welcome surprise. Many hotel restaurants are only average and this one was definitely better than average. The caipirinhas are excellent (get the Caipirinha Especial, made with a higher grade Cachaca), the views are stunning, and the food is very good, with nice presentations. One gotcha is the R$22 per person cover charge for live music in the evening time.
The not so good:
Lots of small annoyances which by themselves would not be a deal breaker but together they are noticeable when combined: No Kleenex in bathroom or anywhere in room, no iron or ironing board, no plug adapters, WiFi Internet disconnects regularly, etc.
Overall for the price was it was reasonable, if you want to be close to Avenida Paulista which was important to me for my work, especially compared to many other hotels in the vicinity that are many times the price.
If money isn't a concern, I would highly recommend the Marriott Renaissance, about a mile further down the same street, Alameda Santos.
Room Tip: Select the highest possible floor to be farthest away from traffic noise