yeah I use Launcher Pro on my tab10.1 and love it. Pkayy, the point of a new launcher is further customization of your home screens. Things like smaller icons, less gap between them and re-sizing of widgets.
I use ADWex on my Tab, even after doing the TouchWiz update. It runs pretty good on it. Because it's an app and pretty much runs in the foreground you get that top bar with the app icon and the settings drop down menu icon showing all the time. (see screenshot)
ADWex as far as I understand is still not really optimized to run on honeycomb or tablets yet, but I got an email back from the developers stating that they are hard at work on an update to address this.
As for one of the other posters questions on the what and why of using a 3rd party launcher. The plain and simple of it... more freedom to setup your devices homescreen to what suits you. On most 3rd party launchers you can choose things like how many row and columns for apps and widgets, number of homescreen and style of app drawers. You can also change things like how the icons and launcher bar looks.
As to what's the best launcher out there... That's totally up to the user. I could tell you its ADWex, but that just me. Others are going to say LauncherPro and some will say stay with the stock one. Try them all and see what works best for you.
Sent From My Galaxy10.1 Class TouchWiz/ADWex equipped Starship