@Minuous
No, it hasn't. It's true AOS 4 uses more RAM to start up but that RAM is actually used usefully, not wasted. And the reason the apps seem to take up more RAM is simply because most of them are ports. If you use designed-for-AOS4 software like SimpleMail, it's almost as lean as AOS3.
@Middleman
First: welcome!

Second: I have to take issue with a tiny point, but please let's not let this get into a C=USA bashing thread - there's plenty of room for them elsewhere...

That said, I was a little saddened by Amiga Inc's stance against CUSA in not allowing AROS to be used and ported over to a modern PC machine bearing the words 'Amiga' - if it had, CUSA wouldn't have needed to go down the path of making their own Linux distro and this would have made everyone happy (that we get a 'modern' Amiga using the latest industry equipment on an established OS). I am not saying this because I am also a CUSA regular - it's just the truth.
That's not what happened, I'm afraid. There were quite a few reasons why C=USA didn't use AROS.
Barry is correct in that AROS isn't ready for mainstream workstation markets - he's not in it for a nostalgia OS, just a nostalgia case. He wanted a modern compatible system that looked old, which is fair enough. AROS is excellent, but I don't think anyone would pretend it's ready for the professional market yet, not least because of the lack of software.
The other reason, though, is that Barry obviously doesn't like AROS. He's made a number of very scathing and undeserved comments about AROS, which shows what he really thinks.
Blame Amiga Inc for many things, but not for this one, this is C=USA's choice. Remember they're not aiming at Amiga users, they're aiming at PC users who just like a bit of nostalgia.
A shame - if they'd run AROS I'd probably have been interested. If Amiga Inc had begged Barry to use AROS, he'd still have gone with Linux, I'm absolutely certain.