I have used zbattle, and so have most of the people in the Z-Net, and we still choose to use Z-Net. As for reasons to switch, well firstly, Z-Net has a customizable chatroom with PMs, which, in my opinion, would work great with online leagues and clans. We also have a send feature that actually works, multiple protocol support (with TCP, the client does NOT need to have their ports forwarded), zip file support, and other addons are being developed for other emulators as we speak. As for easiness to use, I'd say Zbattle and Z-Net are equally easy to use, it's just different.
How would zbattle with an IRC client embedded be any better? mIRC has 13 years of development that you can stand by. And you STILL have not given a SINGLE, I mean SINGLE, reason as to why mIRC is such an awful client. Yes, developers (I'd like to again clarify that I am just a mod, not the developer) can't expect all comments to be positive, but your comments have been more hateful than anything, and are just blatant bashing.