I watched the data connection during my drive in to work, which goes through areas of 3G only, and areas of LTE. In the areas that I know to have LTE, I found that the phone automatically acquired and held an LTE connection. Performance was good (10+Mbps up and down).
Areas that don't have LTE still don't.
This update brings support for the menu button mapped to the recent apps button. It works great, and gets back some screen real-estate. The update does NOT bring quick settings in the pull-down status bar, nor does it bring additional options for long-press power (still just power off, airplane mode, and restart).
Multitasking seems to be about the same, I still find apps closing when I wouldn't expect them to.
All in all, if you aren't rooted, I recommend this update. So far, nothing but improvements, even if it doesn't have all of the improvements that we had hoped for.