Question [Q] Is it worth it to upgrade to Nexus 5?

I'm not sure if it's entirely worth it to upgrade my GNex yet. I want to know what other people are thinking or have done. While my GNex is still on JB stock and laggy as hell it's still bearable for me (most of the time).

I am eligible for an upgrade and my provider is offering me 5 dollars off my current plan if I do upgrade to a Gnex5. Not sure what to do. I know I can root my phone again (although it's glitched and won't let me so I gave up) to put a speedier ROM - I'm still not sure.

What would you guys do, or what do you think? Should I wait for the Gnex6?

Edit: I'd like to note my carrier tends to put out phones quite slowly compared to others.. like Rogers (I'm in Canada on Fido) The upgrade for me would essentially only be 141 "Fido Dollars" they're waiving the activation fee + the difference which is about 50 dollars. The five dollars off my plan is permanent