I've been keeping an eye on this thread so I thought I would try Nova to see if it had something going for it. As I stated before I am a big fan of GO Launcher so be aware that I am biased.
I downloaded Nova and ran it. Went through some of the settings and didn't find anything note worthy. Loaded some icons to my home screen and tested for speed and responsiveness.
As a result of my short evaluation, I don't see much difference between this launcher and most others I've tried, it has many common options but nothing that stood out. Speed is average, nothing special. I am not sure why someone would go to the trouble of creating a launcher that is just like the rest of them. An option here a menu there but for the most part you can't tell them apart. Go launcher is just like the rest of them too except it has a much better user interface, more themes (including Sense), more options, and more widgets. After briefly looking at Nova Launcher I still think Go is the best launcher I have used.
Go Launcher features easy batch loading of icons. Starting from a blank home page with only 13 screen taps you can select and load 10 icons onto a page. With Nova launcher (and most others) it takes 30 screen taps to do the same thing and the interface is not as user friendly. Setting up 4 or 5 home screens takes 10 minutes with Go and takes an hour with Nova. For example, long press on a blank area of screen and Go opens a utility that allows you to select the home screen you want to work with, select what type of activity you want to perform on that page (icons, widgets, wallpaper, theme, effects, etc.), and see a real time graphic of the page you are working on. Fast, easy, I love it!