After having done a little research it looks like you *may* have issues getting the touchscreen/stylus to work with that hardware in more recent versions of Linux .. see here:http://ubuntuforums.org/showthread.php?t=1751149
amongst other places.
It seems "xserver-xorg-input-fpit" has been replaced by using "inputattach" as the method for driving your touchscreen .. so you never know it may even be easier in recent Linux distributions .. but it'll most likely still need some experimentation/tweaking.
so first of all, not having touch a showstopper ?
are you willing to try a recent version of Linux and put some work in trying different things to try get the touchscreen to work .. and maybe still fail ?
or are you happy to use an older version of Linux where the touchscreen does work, but still takes a bit of configuring ?
Installing Linux shouldn't be an issue, but going back to Windows if it doesn't work out may be .. have you got a way of reinstalling Windows if things go wrong ?
also do you understand Linux will NOT run Windows applications .. so what do you generally use the tablet for ?
Are there any peripherals that must work with it (eg. printer) ? .. can you say which makes/models.
No Linux doesn't need AV (unless you need to scan for Windows viruses on a Linux server that services Windows clients) .. it's not windows, and is much more secure from the get-go