GlusterFS still offers the open source software. But since Redhat has re-branded GlusterFS as Redhat Virtual Storage Appliance, I am confused about what will be good for production environment.
Is there any technical difference between Redhat VSA and GlusterFS?
I know that Redhat VSA will come with support but what I am talking about is technical feature differences.
You have already mentioned support, and I'm pretty sure the upstream Gluster will probably have more features than the official product (same as in Fedora vs RHEL), but in terms of stability, RHES is much better - after having gone through months of QA and QE.
In a serious production environment, I'd definitely use RHES and not the upstream build, same as I wouldn't be running Fedora on mission-critical machines, and would use RHEL instead.
Having said that, I'm not a Gluster expert, and there might be additional advantages, in terms of features and other abilities of the product, I just give the obvious, generic ones here.