AUGs are meh. Make sure you've actually tried to use one before you buy it; they seem cool until you've got one in hand. They're actually uncomfortable for most people (especially the magazine release) and just downright odd in so many ways. I know of a few people who like running with AUGs, but most people I've come across who've bought one - myself included - end up getting something else.
Cons you didn't mention about the AUG are the magazine release, the attachment between stock/receiver and barrel assemblies (it's wobbly and does not help to promote accuracy), the foregrip (it's pretty much guaranteed to break off, even on the real gun), and a lovely thing called part ST-21 on the Marui which you will be willing to kill a man to get a replacement for (it holds the gearbox in place; when it breaks [which it will] your gun will no longer function).
If you want bullpup, more people tend to be happier with SA80 type rifles than the Steyr.
I suggest the M4. AUGs are a path into annoyance and failure.