To switch from TouchFlo to stock android home screen you just go into the applications section of the settings app, scroll down to "TouchFlo", hit "reset defaults" or whatever it is, then press the "home" button. You'll then get a dialogue up asking you which app you want to use, "Home" or "TouchFlo". You can either pick one and keep doing that all the time, or you can hit the "use this as default" tickbox and select the one you want. If you choose "Home" and want to change back again in the future, just go back into the Applications part of Settings and scroll to "Home" and hit "Reset Defaults" and press the Home button to get the dialogue back to allow you to select TouchFlo again. The two home apps use separate data so you can safely try one out without messing up your other one.
I had decided before I got the phone that I'd try Touchflo for a week then switch to stock android for a week and see how I get on and make my mind up in week 2. So far I think I'll stick with stock android as it's much quicker but I'm still getting dreadful phone slowdown without frequent use of TasKiller.