I had a very bad experience with AT&T in this store.
I got a new number with the cheapest post paid plan which has unlimited data for US$50 / month (despite telling them that I use less than 5GB / month), I can't even hotspot and they also enrolled me in something called "Protect Advantage" without my consent (no one ever told me about this at any time). I could remove it from future bills, but not in the current one.
I've just discovered that there are much cheaper plans in other mobile service providers with much cheaper (or free) activation fees that work just fine in the Bay Area with hotspot included. I've cancelled before 2 weeks (so no cancelation fee) and now I gotta pay US$116 for 1 month of usage (this same value gave me 6 months on my new post paid plan on a new provider).
AT&T definitely needs to offer more competitive prices, more flexible plans and be clear about add-ons like the Protect Advantage. I am much happier with my new mobile provider.