Im surprised no one replied to this. Although I haven't personally used checkpoint I know several features about it. Astaro covers MOST of them. The only one I know of is you can't VPN firewalls together only VPN TO an ASL box or VPN THROUGH one. Wonder if that function will be added?
I am very familiar with CP. The one thing I can't seem to find is a way to block specific file extension in ASL which I can in CP. The other is that CP supports the CVP protocol which makes it very easy to integrate other apps such as HTTP cotent scanning and e-mail text scanning in the firewall. CP also does PPTP and IPSEC pass through very well.
CP also has fail-over, ICSA Certification (I was told ASL is in process of ICSA Cert) and CP has a huge marketing budget.
Otherwise in my test of ASL I have found it very reliable, fast and secure.