The FA and DS each do a bunch of things the other does not. FA has advantages like a tonewheel organ engine, the supernatural VA synth engine, an assignable sub out, the big color screen, the sequencer, the ability to load two expansions instead of one. BUT the DS also has lots of advantages over the FA. I think that a lot of the basic sounds of the DS (from fantom and newer) are better than those in the FA (largely from XV-5080, except for the supernatural sounds). The DS lets you load custom samples playable as instruments from the keyboard, the FA does not. The FA cuts off all sounds when you switch from one Studio Set (equivalent to DS Performance) to another, the DS does not. The FA has more effects units overall, but you can only put one insert effect on a sound, whereas you can put three effects on a sound on the DS (one way to look at that is that the DS could have an advantage in playing 1 or 2 sounds in live performance while the FA has an advantage when playing 16-channel sequences). And others. For me, the DS was better than th FA, but for others, the FA can be better, it depends on your priorities.