As a previous owner of a Galaxy Nexus and owner of a Nexus 5 (for a year). It's like comparing a rotten apple with a big nice Orange. The Galaxy Nexus was nice until it got the 4.2.x release imho, after that was pure trash. The Nexus 5 is an amazing device, the camera is not bad as people say, it's very fast and the screen is nice (GN was better for my eyes). And KitKat was the first release at the same level or better than iOS in terms of usability and quality. You won't be disapointed with the N5. Just make sure you buy a case, the back is very slippery and the device it's big :)
As for iOS devices i had a iPad 3, which was the worse device Apple made due it's slow processor. And also I got it 1 month before the iPad 4 release. So really bad timing.
As for iOS devices i had a iPad 3, which was the worse device Apple made due it's slow processor. And also I got it 1 month before the iPad 4 release. So really bad timing.