How fast is this phone using launchers?

[omnius]

The reason I'm asking is that I've tried this phone in the store as well as watched the video reviews and yes, the UI is really, really fast and smooth.
I'm curious if anyone has installed a 3rd party Launcher, like Nova or something without being rooted and noticed how the speed is after they did that?

 

[Little Darwin]

I use Nova Prime on mine, and it is very smooth.

In my limited experience using 3rd party launchers, they usually work at least as smoothly as the included launcher for any given device.