I just bought a Rollei P66A on my recent trip to Germany. I cannot say much about it yet, as I have also just started to explore medium format photography and am waiting for my first slide films to be developed...
I also got a Rollei 35mm projector, and just looked at my dad's slides from 1964... quite a joy. Most slides are still in good shape, I am not sure what film it was. They were all hand-mounted by my parents into thick glass-only mounts.
mtjade2007 said he has a P66 and it is a medium format and 35mm projector? I don't quite understand how it can handle both format unless the 35mm positives are mounted in 7x7 slide mounts?