I've recently been getting back into taking and viewing slides and I'm really enjoying it. There's something quite magical about looking at slides on a lightbox. They look like precious jewels to me.
I bought a Pradovit CA2500 with the Colorplan lens for 35mm, and a Rollei 66 projector for 6x6. I don't have anything to compare them against, but the projected slides look amazing through both systems. In some ways the 35mm slides are most impressive because there is so much detail and so little grain. Obviously, the medium format slides even more so, but I'm used to those already looking very detailed.
Shooting slide film for projection is having a big positive impact on how I take photos. The higher cost per shot means I'm a little more careful about my subjects, which is resulting in a very high hit-rate per roll. I shot a roll of Velvia on holiday and out of 38 photos, I've marked off 30 for mounting. And believe me, given the time it takes to mount them (I'm scavenging mounts from old slides), I'm very selective. The inability to crop means my framing has improved, and I'm now using a spot meter and learning to use the zone system properly. It's a fantastic learning experience and definitely pushing my skills up a notch.
Next project: learning to shoot and process my own B&W slides. Bring it on!