It's not difficult to do but time consuming and set up costs can be prohibitive. The initial cost was about £350 and for that I got the machine and the leads and 2 carbon rods. Also a pack of 3 swabs you put over the rods, rubber gloves,gold plating solution, spray for water, mixing containers and a CD explaining how to plate. Since the initial outlay I have bought silver solution and more recently the solutions that you mix which is trial and error. You also only get a tiny amount of the solution for £50.
For pens you need smoothing sticks so you don't get a bumpy finish after plating. This can take the longest time. Also before starting to plate you have to clean off with something called MPU. The plating is the easy bit if you can get the clip to stay in place. I use a pressure bar attached to the crocodile clip on the red lead and put it under the clip. It must touch if the clip is to be plated.
The other thing is some pens just don't take the plating. Must be to do with the base metal. When it does work the results can be very pleasing.
The other thing it does very well is replate steel nibs.
I have spent well over £500 trying to get it right and I'm still very much a novice but a determined novice.
Just finished a Skyline cap and I'm very pleased but can't find a before picture but believe me the cap was a mess but looking good now.