Customizability and tons of more options. With an aftermarket launcher, you can pretty much tweak the look and feel of your device to suit your needs and desires. You can make it look like "your" device. It doesn't hurt anything to install one of the free launchers and try it out. I would actually recommend it. I personally use LauncherPro but ADW and GoLauncher are pretty good choices as well. If they don't suit your needs then there are many other options on the market. If none of them spark your interest then the stock launcher may be your launcher of choice. It's all about options and choices...Take that iPhone guys!!!
I have not found a way to switch without uninstalling ADW. There used to be (still is?) a "home switcher" app in the market. I have used it in the past on other phones I've owned. I don't know if that would work on our phones or not.
The home switcher app should work. Otherwise, you can go to manage apps from settings, select the launcher and remove default. Once you hit your home button again, it will ask you to select your default again.
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