Hence the correct answer as in most tactical aviation questions is: It depends. Both obviously work, both obviously have flaws.

Ab initio students seem to do better with a dedicated instructor (who is available when they are...) who can provide encouragement and instruction while following their progress. They are familiar with what the student is doing right, wrong, where they are weak or strong, and they can base their instruction and next ride on that knowledge.

Students with some avaiation experience, or who are more driven like Flubber, would do well in platoon systems, getting varied view points and experience and being able to fly each time they make it out to the club.

I'm lucky in my club, and they do it both ways--mostly we try to pair a new student with one instructor, who does conduct ground training sessions, until they are ready to solo. At that point most of our instructors have their student fly with another instructor for the differences and for a separate evaluation before they solo.

For me, I wanted to fly everytime I showed up--even if my instructor couldn't be there. I took responsibility for my own ground school and studies (attending sessions of other instructor when they let me). But having a military background, I like flying with multiple instructors.

Either way, continuity of flying and training is a major issue--paired instructors are good, but if mutual instructor or student schedules make flying an every other weekend or worse situation it's not ideal. The platoon system helps solve the flying continuity issue, but not the instruction and personal following continuity. Being a weekend only type of sport makes it a tougher nut to crack.