In terms of performance, it's honestly difficult to give a final verdict. Everything seemed crazy fast when it came to launching and switching between apps. That's often the case with a fresh Android phone, however, so we'll need to spend more time with the device before we can render a
Speaking of rendering, the old bugbear of Android has always been scrolling performance. Especially in Chrome, there's always been a sense of lag that seemed completely out of place on top-tier devices. On the Nexus 5, we're very sad to report that the situation doesn't seem any better. There is still not a one-to-one relationship between your finger and the screen, and it's still crazy-making.
I wasn't expecting one-to-one ever, nor am I bothered by that. But thought this is worth sharing.