There'd be little difference on most systems as they arn't new installs of the operating system. Even StyleXP and Windows Blinds is flawlessly fast when the install is new. After six months or so I still think there'd be a very noticeable difference, even if mIRC itself wasn't as slow as OS-wide theming system gets. I think there is room to give people some options here though as history dictates, when this happens the option of a straight-foward way of doing things usually disappears after a while and the market is usually asked to accept what is thrown at it.
