Unless you don't mind rooting your device, then go with the Razr. If not a rooter, then the GN is your better bet.
I say this because none of us know what's in store from Google in the next few months. They might provide some date between now and the next major release that's simply incredibe and you may be left out in the rain.
From what Ive noticed, and please correct me if I'm wrong anyone, but most Android phones usually only get one major update.
Limited history has shown even the Nexus is only good for maybe two big updates.
But again, the decision is yours.