Its terrible wifi, dont even try to do more than check your Facebook or slowly upload photos. The PING would be very very high due to it being satellite and the download and uploads speeds would be sluggish at best.
On-board wifi is really for the people who NEED internet access, for everyone else its a littke bit of a waste of money. Try it once! But i wouldnt do it more than once, €20 is a nice fork out for WiFi that'll make you cry.