I mean who wouldnt update their phone if given the option to do so? Seems simple enough to me. The second they make a Nexus that isnt a battery disaster I'm going right back.
The program is good, only thing that sucks is if you have Jump on a current phone you can't use your Jump to clear the balance to move to the On Demand. For example my Note 4 has about 460 remaining, trade in is $318, I have Jump and can get into a new phone and clear the balance if I want to, but not on the on demand. I would have to pay the difference between the trade in and what I owe.
Also at the end of the lease you pay what would still be owed on the device or trade it in. Or if you cancel while in a lease you have to pay the lease off and trade it or or pay the lease+phone to own the phone.
As an employee when we first heard lease we were all like

But that 3 trade in's a year for someone that likes to always try new devices is
Might try out an iPhone though with the problems I have been having lately, or the G4