Check this out

[cobro]

ISPCONFIG

When we purchased several 64-bit quad-core servers in late 2007, we reviewed available control panel solutions. The package ISPConfig was selected since it appeared much better than other control packages and was under open source license (i.e. free for us to install and use).

ISPConfig is not without problems, but we have extended this control panel solution with custom patches for grey-listing and spam filtering, propagating domain name service (DNS) records to our production name servers, and integrating it into our system-wide backup.

SUMMARY

Perhaps the biggest drawback of all control panel solutions is that it is not easy bypassing the panels and doing custom configurations for special-needs clients. It’s pretty obvious that labor costs much more than hardware or bandwidth nowadays, so automating as much of the account setup and maintenance is the key to staying profitable.

As for us, we’ll keep using ISPConfig and passing the cost savings for hosting back to our customers.

and the link http://blog.gorgeswebsites.com/2009/...el-comparison/