Hi;
The problem with other peoples opinions - is that they usually display a loyalty to whatever it is that they are currently using - or what they are selling.
This does not mean that someone using a particular keyboard - or selling a particular keyboard - may not be telling you what they honestly believe - but ownership breeds a certain amount of emotional attachment for a particular instrument - as does having a dealers franchise.
The X1 is a fine keyboard as is the Yamaha and the Technics.
However they all have different operating systems - different learning curves - and different problems.
Keyboard weight - the ability to have a good system for your settings - midi playing - sequencing - editing - storage - arrangments - sounds - etc. these are parameters that mean different things - to different people.
The problems of one brand may or may not be important to you.
If they are - wou may have an expensive toy sitting at home - that is useless outside.
The words in Latin are " Caveat Emptor " meaning - buyer beware.
Go to all the dealers - check them all out for your particular needs - perhaps you can borrow a demonstrator for different units over a week end.
No one should substitute other's opinions for their own judgment.
Glowing testimonials - are meaningless - unless you buy - knowing for yourself the deficiencies - they are real - they do exist- and they are not always " up front."
Not all factory defects - are solvable simply by sticking in new "software."
Jerry