And his trade mark spin.

No one else in the world does it, Man or Lady. Artistry and flexibility are the two words that come to my mind about Shawn Sawyer. He is truly special, outside of Gary Beacom the mad genius on Ice.
Indeed! He is one of those whom Scott calls "Truly Special", and in Shawn's case he is truly right
Just watched that SA AiW that Mrs P posted and all I can is
The Jason vs. Shawn comparison the way I see it (and I'm wiriting this as Jason's biggest fan):
Flexibility:
Shawn: Defies belief, unique
Jason: Hugely impressive
Artistry:
Shawn: Faithful to the theme, excellent interpretation. Attention to every detail, no movement is devoid of meaning. Most everything is to the music. Plays to the audience and brings them in. Adds little touches to the footwork and transitions that relate to the theme (crisp hand/torso/head movements, arm/head movements when going into a jump).
An example from this program: A little swashbuckling swordplay towards the judges mid-footwork!
Jason: All of the above, and he will (I say selfishly/hopefully, because they make my heart beat the fastest) add even more of those little touches. Or not, if he gets the quad and needs to reserve energy!
An example from T&I: Going into the 3F3T left hand on heart, head turned to look back with right hand extended backwards as though reaching out/in a silent farewell to Isolde.
Technique:
Spins:
Pretty equal. Shawn has the edge in flexibility, Jason a slight one in speed and centering
Jumps:
Both have really beautiful air positions, landing positions, arm positions on landing, and transitions. Both carry the free leg very low.
Shawn did tend to pop jumps and step out and occasionally kick a decent blur of snow with his free foot, while Jason's problem seems to be, occasionally, clear two-footing and URing, not popping/stepping out so much. And when he does pop he can think on his skates and triple an intended double (TEB).
On the other hand, Shawn had better flow out of jumps; Jason does have a good running edge, too, but not all the time for sure. Especially 2nd jumps in combo and loops seem to land and just...stay there?
MiF:
Both have spirals to DIE for - if only they had more time to perform them!
Shawn looks to have an edge in speed, and dare I say it skating skills

But then he was much older than Jason in the videos I watched, so Jason has time to develop there. Or I may be wrong because I'm a laywoman: to me Jase just looks a bit more laboured on ice sometimes, while Shawn didn't.
I'd say their footwork is pretty equal; both have nice crisp, controlled turns and steps but Jason, again, seems to have less speed and can look slower.
Head:
Shawn: You never knew what to expect. He could do great or he could bomb, and previous competition results seemed to be no indication.
Jason: Unusually consistent; he rarely falls and his scores tend to get bigger every time he performs a program, which shows that he learns from his mistakes. Even in the most nerve-wracking competition that exists - the Olympic singles - he managed to finish upright and his score was not that far off his PB (I'm still very surprised that that happened, I was expecting low-mid 140s and thinking I may be too optimistic here; certainly didn't expect a score not 6 pts off his PB)