Clays are actually pretty good smokers. Had the pleaure of meeting Marcus at the Chicago Pipe Show last year. A great guy with a long family tradition of clay pipe making. My brother and I became interested in clay pipes when we stumbled upon a colonial plantation site on our farm with a treasure trove on 17th and 18th century clay pipes (
Colonial Clay Pipes Found in Virginia). It was actually these clay pipes that first got us interested in pipe making. There's definitely an art to making a press molded clay pipe. For us it involved a lot of trial and error in learning the skill, but the end product is definitely worth it.
When smoking a clay, it's definitely a pipe you want to smoke slow. As others have said,you really have to hold the pipe by the stem as the bowls do get extremely hot. However, the thicker the clay, the less heat that they transfer through the bowl. We make a couple late 19th century clay pipes that have thicker walled bowls than their colonial counterparts and you can actually hold these bowls for awhile, but eventually even they start to get a little too warm for comfort. Colonial clays were fairly thin walled pipes and they will heat up very fast.
While clays certainly have their negatives,they also have their positives as well. First of all, there's no "ghosting" with a clay. Clays are excellent for sampling tobacco blends as you get the true pure flavor of the blend without the pipe material affecting the flavor. Clays like cobs also wick away moisture so you typically don't have any "slurping" issue when smoking a clay. And of course, theirs the nostalgia of smoking the pipe that started our favorite hobby centuries ago.