I have used the service for three times already and the signal was consistently strong, at least from the coffee shop at Sky Garden where I have been going.
The connection was being offered by SM itself and not by the individual shops located at the premises. Also, the connection was unsecured and did not require you to secure a password from anybody.
This was in stark contrast with the Wifi connections available at Trinoma which appears to be from individual shops and mostly secured, thus, needing passwords that you usually have to get from the shop owners.
I have thus added the SM Annex, Sky Garden and the Block to my list of free Wifi hotspots in Quezon City, perfect places for one with a Wifi-ready laptop.