Here are some Control Panels to evaluate, anyone interested in comparing them?

http://www.evolutionware.com
http://www.cpanel.net
http://www.ispdb.co.uk
http://www.plesk.com
http://www.psoft.net
http://www.smarthostingtools.com
http://www.sphera.com
http://www.freevsd.org

I have looked around exstensively at all of the interfaces mentioned and yes, most of them are very good products. The only issue that I have had with most of them is the lack of named based hosting support in terms of allowing a client to manage databeses etc via thier interface.
I currently use Cpanel 3 with http://www.jtlnet.com . I think they are a VDI host. It is constantly being updated with many new features and has kept my clients happy.
Regards,
Mike