We are happy to see the great interest in Sitefinity 4.0 and the desire of people to go live with it before the official release date.
As Sitefinity 4.0 RC is not an official release, there might be some issues that we are still unaware of. That being said, we encourage and support everyone, who is willing to explore Sitefinity and deploy a production website with it, even prior the official release.
If you understand the risks of going live with the Release Candidate, I would recommend you to contact the sales team directly at firstname.lastname@example.org
and discuss the details with us. We will be happy to assist further!
Grisha 'Greg' Karanikolov
Sitefinity Solutions Engineer