It looks like AROS has not been updated in ages. I'd love to try it again.
Actually AROS is updated every day and is moving along nicely in recent times.
The website layout is a bit confusing though, the snapshots (which arent really updated anymore) are at the top of the downloads page, which at a glance makes it look like aros itself has stalled. If you scroll down beyond that you'll see the nightly builds. Additionally the main page status updates arent updated often.