Best for high load websites, 2 or 3?

[FeraTechInc]

Is ISPConfig 3 or 2 better for websites that are high load websites?

We have switched from ISPConfig 2 to 3. However, the interface in 3 isn't very user friendly. Also, since we do all the hosting and never use or create clients we have lists of 300 e-mails we have to go through any time we need to administer anything.

So from an administrator stand point ISPConfig 2 is much more user friendly for us and the way we manage websites.

However, we want to make sure whatever we are using will be able to handle many users.

We are also looking at building a cluster server as well. It seems like this has not been done much before and for that it seems like ISPConfig 2 would work best. ISPConfig 3 might be best if we simply wanted to spread the load over several individual servers. Or at least that is our justification.

Any input would be appreciated.