I would prefer a workstation with good piano sounds (but will not consider a Yamaha, since I do like their piano sounds but not others) and ideally one with a good feel to the keybed. Weight is not an issue it is for home use only.
If by workstation you mean a board with a full built-in multitrack sequencer, at the price of the FA (or lower), I think the only other options are the Korgs. Or if you're opening the field up to boards with fewer and non-hammer keys, there are some Casios, notably the MZ-X500.
The FA 07 that I played in the store had a good feel and I could certainly live with one or maybe an 06 if that has the same keybed which seems to be velocity sensitive synth.
FA-06 action is a step down from the FA-07 action.
I did try to see if the SST worked on the FA and primarily it did, where it did not Fx had been applied to the sound.
IIRC, on the FA, SST works in two ways, with different limitations:
...Within a Studio Set, you can seamlessly switch among any set of 16 sounds you have defined, but not to anything outside the set of 16
...When playing individually tones, seamless switching works from most sounds to most other sounds, except there may be a momentary effects-related glitch; and it won't work at all if switching with a SuperNatural Organ tone.
My thinking of the FA v DS is that the FA has a better interface and a much superior inbuilt Sequencer. Creating the layered sounds and split keyboard on the FA looks far better than what I was used to with the Kross. I cannot remember what I did on layering on the DS when I was shop testing one.
FA does have the better interface overall, Both have dedicated front panel buttons for split and layer. DS does have a better interface for managing 2-way splits/layers, with its dedicated sliders for the volumes of the two parts, and a split interface that makes it particularly easy to change the octave of either sound on the fly, or change one of the two sounds without impacting the other.