Personal hotspot - wifi v. bluetooth?

[TripleP]

When I use the personal hotspot feature (iP5) with a wifi-only iPad, should i use wifi or bluetooth? What are the pros/cons of each, in terms of battery life, data speed, and security (I'll be using daily on a commuter train)? Thanks!

 

[dhy8386]

http://www.gizmodo.com.au/2011/03/ios-4-3-personal-hotspot-battle-bluetooth-vs-wifi/

http://www.wifinotes.com/bluetooth-vs-wifi.html