As most here know, I've been doing Readings for over 30 years but I deliberately avoid situations in which mediumship is part of the scenario. That said, I'll simply say that anyone that does that sort of work has to be special because it is a creepy feeling, having another consciousness literally working through you. I've had it happen twice and it freaked me out something terrible. While I've learned to understand it, it is not something I think I'd ever seek out to do full time. On the other hand, if spirit must convey a message and I'm the chosen vehicle... well, I guess I'll deal with it.
I've seen and encountered far too much to say it's "all" horse pucky but I do know that 90% of the ghost folks encounter can be readily explained, just as the information conveyed in a Reading can.