Firstly, as I have the X1 HD model, I have all the previous MS series of styles in which I agree that the Dance styles are better than the X1's but NOT the Techno & HipHop section of styles as on the X1 they are very professional and modern, only the Korg I30 before it competed in this area I feel.
The Yamaha's Techno, Clubdance, Rhumbas, Beguines, and a lot of others are spin offs of the PSR8000's styles, that slightly dissapointed me as theres not that much difference in the arrangement of the styles, thus I ended up playing the same familiar songs I used to with these styles when I used to own the PSR8000!
As for your second question, I know not of this feature, how does the cut and paste work?
The custom/factory feature I have not used either because i have so many styles on the X1 that im almost lost! I have no intentions of modifying the internal X1 styles, but I am experimenting with the PSR & GEM converted styles.