Like the other 10 threads about basically the same thing...Is it the only upgrade you have for another 2 years? If yes, then I'd say no. An amazing phone for sure and I love everything about it, buuuuut if it doesn't appeal to you immediately and you like your Nexus, I see no reason to switch over just for the hell of it. You can wait till the end of the year, THEN use the upgrade, and that way you'll have an upgrade available every year.
Never used a Nexus, but as long as updates have resolved all the issues it initially had, then I don't think it'd be worth it.