I used the BrakeAway for years on my ST1300. Tricky to get the alignment set up properly, and if I had occasion to do anything with the front brake assembly, I sometimes had to fiddle with it a bit again. But it worked flawlessly, and with the exceptions noted in the previous sentence, required NO maintenance adjustment. Contrary to one comment in here, it is also friction-based, but I didn't fiddle with the friction adjustment, ever. It does occupy some real estate on the handgrip, though.
Many years ago I had a VistaCruise, but it wasn't well made and had excessive slop in the linkage, making it a subpar device. They may be better now, so I no longer have an opinion.
I have found throttle friction devices (sorry, virtually no product mentioned in this thread is an actual cruise control) only useful for short durations, but useful nonetheless in that context. So I'll probably add something or other to the NT.
I have a CrampBuster right now and find it to be the most effective gizmo for everyday use. And it's embarrassingly cheap. Not worthy of the term "farkle".