Also, "level up bonus is 100% more Damage for 60 seconds and full health." 

Source(s): http://forums.gearboxsoftware.com/showpost.php?p=4849229&postcount=4 & [www.youtube.com/watch?v=t2YYwM1coOU#t=35m13s][1]


  [1]: https://www.youtube.com/watch?v=t2YYwM1coOU#t=35m13s