I believe the '97 to be easier to load/shoot for a newcomer to CAS because it allows for sloppier technique without time penalty to the shooter.
If you grab two shells from your belt, you can slap each one individually into the open ejection port without even looking.
With a SxS you have to be much more precise in placing your shells in the chamber.
The SxS will have faster split times regardless of how long it takes you to load. (Think poppers and clays.)
It will take longer to load one in the chamber and then one in the magazine of a '97 than it will to load two in the chambers of a SxS, providing you don't fumble with the SxS.
If you can grab four from your belt in one hand (and some can) then the '97 can be run equally or faster than a SxS in a four target delivery. If you can't repeatedly and reliably grab four, you can have a really bad train wreck slowing you down even more.
Also, the SxS needs to be set up to where it will fully open in order to get both shells in the chamber quickly.