I have one of (in fact quite possibly THE) original large model switchboards made in the 1970s by the acquaintance of mine who actually created it (based on a similar effect with 2 bulbs and 2 switches marketed, I believe, in the 1950s) before he sold the manufacturing rights to Wellington. He is (or was) an amateur/part-time magician and hobbyist who works (or worked) at the Naval Research Laboratory here in Washington, DC.
IMO, the only one to use is the large model. The fact that it must be plugged in is a distinct advantage because, psychologically, most audience members assume that since it is plugged in to an outlet it is not subject to electronic or remote manipulation (even though that is an absurd assumption).
The inherent problem with the effect is that, as several poster's comments suggest, it is difficult to develop a presentation that does not come across as a puzzle. And any magic effect that is presented as a puzzle is virtually challenging the audience to figure it out thereby completely destroying any semblance of "magic" -- and once a spectator seizes on an explanation that is intellectually acceptable to him or her --no matter how far off the mark that explanation may be -- the "magic" is gone and only a toy and a puzzle remain. Accordingly I'd be willing to bet that an even higher percentage of switchboards sit unused and gathering dust in people's closets than most other tricks folks bought because they were fascinated with it and never bothered to think about how they would actually use it in a performance.
I also have to add that IMO the small, "less expensive" version seen in the aforementioned You Tube video is not only a poor substitute for the larger "real thing," but that has to be one of the sorriest presentations of any trick that I've seen in a long time. (I'll leave it to Wellington and others to address whether or not the item seen in the video is an authorized version of the prop.)