Although i'm disappointed the Galaxy Nexus never got an official Android 4.4 build, the unofficial Cyanogenmod 11 (Android 4.4) builds for the Galaxy Nexus are so smooth, even compared to 4.3 which I thought was had a nice performance increase over 4.2.
I was thinking about getting a Nexus 5, however given how well early 4.4 roms are on the Galaxy Nexus i don't think ill end up buying one now. Google have done a great job optimising Android 4.4 for older / lower end hardware it appears.
On 4.3 my Galaxy Nexus used to average about 100mb of free ram, however running the exact same apps in the background i now have over 200mb of free ram. I simply restored all my apps / settings with Titanium Backup after wiping / flashing Cyanogenmod 11.