I answered this on another forum, but FWIW, I think TMR is a good alternative because it offers a low hassle method of liquidating the asset, expertise in pricing and advertising, usually a quick turnaround, and, most importantly, finality. If the system is a significant asset-six figures-all that can be important if your heirs/executor don't know anything about this stuff. TMR makes money, so your estate won't get top dollar. But nor do you risk a long, frustrating dispute with a buyer in which your heirs are at a big disadvantage. A prearrangement with a dealer to consign is another option but will not offer the same level of insulation and finality.
Just leaving a note or informal instructions may not be enough. If your instructions are not in your testamentary document, you could unintentionally dispose of your equipment in a way you don't intend and will make liquidation harder. Think about putting it in your will.
My kids only know my system is dad's "stuff'-no idea what it is, what it does, what its worth, how to sell it-left on their own, bad decisions are entirely likely. Obviously, the more valuable the system, the more care is in order-a $20k system is one thing, a $200k system requires a different level of planning.
Unpleasant to think about, but a lot of us are pretty far down the tracks-I don't buy green bananas any more. This is an important, but easily overlooked planning point for the inevitable date with Mr. Bones.