I have no problem with the 10 user limit, but I'm already over the 10 computer limit with just me and my wife.
The thing I'd really like to see in an "advanced" version is Exchange "Lite" email for my personal domain. I'm currently running SBS and it's way more than complicated than I want, but it's the only thing that gets us push email to our Windows Mobile phones.
I doubt we're the only people that want to have a *simple* way to do our personal e-mail to our phones and via OWA.
Email like this is a feature that I think would justify an advanced version. Unless you are adding big features like that just let us buy extra licenses.