I had the Note2, bought the Nexus4 and sold the Nexus4. I did not like the display on the n4, too yellow form me. I thought battery life sucked on the N4 until I put Cyanogenmod on it. I thought phone sound quality on the N4 was bad and people complained about the background noise in noisy environments. I really don't see the big deal about the updates, CM turns them out pretty quick. The Samsung leaked firmware comes out regularly, I don't see a huge difference between 4.1.2 and 4.2.2, nothing that gets me excited anyway. I don't even like the Google launcher, I always end up using Apex launcher.
For $350, the Nexus 4 is a great phone, but compared to an Iphone5, Note2 and S4...sorry, it's not there. It did open my eyes to LG and I think they will have a really great phone this year or next, they are finally catching on.