So True is not at all Roland's top piano. The So true patch is old technology from the Fantom S series and found on the XA as well. The XA has the same 64 MB ssample rom as Fantom S. The X has those 64 MB, plus another 64 MB, most of which is used with what they are calling "ultimate Grand". Each of the 88 keys is sampled at 4 velocities in stereo. This piano is not to be found on the fantom S or XA. But, if you did buy a Fantom S, which i'd recommend above the new XA, you could buy the SRX-11 Superior Grand expansion board which uses the same sampling techniques as the X's Ultimate Grand, only supposedly even better.