Sorry CBoy, in order to enter an intelligent discussion about why it's better, we'd need to tailor the discussion to your specific needs. Start by telling us something about yourself and what you need from a keyboard... Might turn out a CP4 Stage or a Tyros5 might be a better choice for you. Each of these has a different target customer. And different capabilities.

We can tell you that the Montage is currently in production, the Motif XF is now out of production.
To learn all about what's different and what remained the same you can start here