chrikenn,
I don't know that answer, but it is a good question!
I use GoLauncherEX. I have tried several of them too. I am pretty firmly set on GoLauncherEX because it has just a ton of free themes and add-ons like GoSMS, GoCalendar, GoContacts, GoWeather, GoLocker (screen lock), etc...
The GoSMS is like Handcent. It can be themed out and there are tons of options like being able to handwrite (scribble) a note and send it as a text. The GoCalendar is like my previous HTC Sense calendar.
Coming from a Sense ROM (Sprint HTC EVO and EVO 3D), I have found the "Go" products to best give me the feel of a Sense experience.
I would be interested in knowing the answer to your question too. Once rooted, I would imagine one could uninstall TouchWiz if so inclined, but I am unsure. I have found every launcher to introduce an extra moment of lag when I wake the phone, but it is really brief and livable because I love being able to theme everything out and get custom widgets. The bonus is that most of it is for free. I have not purchased one add-on yet and I have everything I could want and more.