I personally want the Nexus 4 - been drooling over it for a couple of weeks, but just haven't pulled the trigger yet. I have no desire for any other phone. I love my Nexus 7 tablet, and so I know I am VERY happy with Jelly Bean (Android 4.2.2).
I like that you can purchase the Nexus 4 unlocked from Google for a reasonable price (well, compared to other smart phones!), and then use it on TMobile or AT&T. While technically LTE SHOULD be better than TMobile's HSPA+ 4G, reality is that TMobile's 4G is often as fast as the LTE networks, although your mileage will vary based on your specific area.
I also like that the Nexus 4 should get Android updates pretty quick after Google releases them. The problem with other phones is that the carriers always overlay the base Android release with their changes, so it takes forever for them to push out the updates.