That's definitely a sweet deal. So far there's no indication Mobilicity will unlock, so for the time being it looks better to start with Wind using their 6 months at 50% off (for $27.50), 3 months in you get it unlocked, and when the 6 months are up switch over.
The word 'Pentaband' means '5 Bands', from the Greek word 'pente' meaning '5'. For a phone to be pentaband it has to support 5 bands. If the phone has AWS support, it doesn't automatically mean that it is pentaband. The reason Wind and Mobilicity users like pentaband phones is because the reverse is true. We're not the only ones who like pentaband phones though, so please stop referring to phones that work on Wind and Mobilicity as pentaband. It causes unnecessary cofusion.