The size difference is remarkable. The X can kind of be a one handed phone. For most normal size hands, the Max models are 1.5-2 hand devices. You can make it a one hand device, but it's really cumbersome at time.
The big screen is really great for viewing, though, and the battery will be a huge advantage. Also, this camera system looks significantly better than the XS let alone the X.
In short, it's a very big improvement, IMHO, but be read for the size.