I've been watching Onavo's development for the past couple of years, and I've used it every once in a while, and I saw a bit of data saving happening. However since I only tried it on devices like the N4 which I had terrible battery life starting with, the connecting with the VPN killed battery life even further.
I'll be giving it a run again with my N5, forcing myself to use it for a week straight. The only thing I want to get rid of is the VPN Icon in the status bar.
I'm curious what everyone's opinion on Onavo's Data "savings" are. As well as, if you've used the app, how was your experience?