Am I being thick or do you actually mean the X-03? I haven't really heard the X-03 in much detail but I have listened to the X-03SE extensively because my dad uses one. Unfortunately, I haven't directly AB'ed with another player, so I really don't know how it fairs against competition. I've listened to the X-01 Limited and P-01/D-01. Iirc, the X-01 Limited was not significantly better than the X-03SE. The X-01 Limited is more transparent but that's about all I got from a short comparison between the two (via Chord/JMLab system). The P-01/D-01 was noticeably the best of the three because I was able to forget about the gear and enjoyed listening to the music the most.
Judging from the small difference between the X-01 Limited and the X-03SE, the latter may not be such a big step up from the SA-60. The X-03SE may use higher quality parts (eg high purity internal wiring, wbt nextgen RCA jacks, VRDS NEO transport, two DACs per channel, etc...), but it down-converts DSD to PCM before D/A. The SA-60, iirc, does native DSD D/A conversion.
The Meridian G08 I heard in a completely different, considerably cheaper system (Mark Levinson/Magnepan) so I can't really comment on how it compares.