I didn't intend to put the cart before the horse. I was just at Ensims site and felt compelled to post.
I actually have twelve frustrating weeks invested in trying to determine what direction I want to go in. Open or Microsoft. I'll be starting small with 4 servers in a colo. I still haven't been able to decide. Can you recommend a good forum to discuss this topic?
Our system use FreeBSD and Jail as a base... but we have improved it a lot, that is why we have decide to call it IspBSD, because it is a full OS by itself.
The system is very strong, just test it for free if you like (www.ispserver.com)
Jail in not good enough as a standard version, but we have make our own jail and it is very powerfull.
ISPserver Virtual Dedicated Server are very powerfull and more secure than a Dedicated Server.
It depends on what you want to do. If you want to provide multi-homed (real IP), and virtual solutions without ssh and telnet access, then Ensim. If you want a totally virtual looking OS environment so you can give SSH and Telnet access ability to the customer, then Spera. I would use both, if I were you, but each for the different packages, if you plan to do all those package. These days, people need SSH and telnet less, and less, and most provider simply don't allow it because those who do seem to eventually go out of business because of a hack, and everything going down, or getting lost.
If you want, I got a company you provides colocation, and they are exprecienced with control panels like Ensim, and if you ask they can get you a server with the Ensim on it. Let me know.
Those reading this, please don't reply with ... oh you can give telnet and SSH with Ensim too. Yes, I know, but I wouldn't.