I've tried it at the following areas:
Building A 2nd floor - good
Building A Upper Ground - good, you can also surf from McDonald's
Building B 2nd floor - good and you can easily check out stuff while inside Electroworld; gets spotty at the foodcourt
Building B Upper Ground - good, stay near the window if you are dining at Jollibee; none inside SM Hypermarket
Building B Lower Ground - good especially at the middle, you can surf while having your hair done at Going Straight!
SM has free wifi at the following malls: Marikina, Megamall, Mall of Asia, North EDSA, Cebu, Bacolod, Baguio, Pampanga, and Iloilo
Thank you SM for this early birthday gift! I just hope though that next time there won't be a noisy! noisy! band (they were good though) since it gave me a very bad headache.