I'm a recent Mayo grad, so I completed two of my five final clinicals at Mayo Rochester. Mayo uses a collaborative model for the majority of their clinicals. Both my experiences were organized in a 3:1 system, with three students working under one CI. In these arrangements, CIs do not carry their own caseload. Instead, their only job is managing the students and their patients. In both my clinicals, we started at a partial caseload with our CI present during our sessions. By the end, we were managing a full caseload (or nearly so, depending on census) with our CIs primarily serving as advisors.
I really liked the collaborative model and actually, my Mayo clinicals were some of my favorite clinical experiences. I enjoyed learning from the other students I was with, as well as my CIs. I never felt like I was wanting for individual attention, but I wasn't afraid to speak up and ask questions. If you're shy or nervous about what the other students may think of you, you may have to push yourself a little more in this kind of a setup.
There's been some discussion of the collaborative clinical education model in the literature. Mayo's program is described
here (link is abstract only).
Again, I only completed rotations at the Rochester campus, so I can't speak for the Arizona or Florida locations. Not all of the sites at Rochester use this model; some only accept one student at a time. If you have more questions or would like to know more about a specific site, feel free to PM me.