I owned a Colibri and had no problems with it. But I do agree that each unit is unique, like a custom built automobile that was built to someone else’s preferences or that you buy second hand. Nevertheless, they are "special". I think vdH does not disguise this quirk, because on the inside of each box you find the specs for that cartridge that came in that box. And if you buy a different Colibri with the same options for wire, materials, and etc, it is likely to sound a bit different and to have different specs. Any buyer should take these things into consideration, but that does not make the cartridges "unreliable". Unpredictable may be a better adjective. But never bad sounding.
What Are The Differences Between The Vandenhul Cartridge Families
It seems like VDH had an abrupt departure in his cartridge designs awhile back. There were the metal body ones like the Grasshopper and other types, and then all of a sudden the open architecture of the Stradivarius cartridges appeared. Seems like the specifications also indicate a fundamental shift in design philosophy also. Yet I believe there is one hold over, or at least the silver and gold versions of the Grasshopper stayed around longer than the other ones.
Does anyone know what changed, and what the corresponding differences in presentation might be? I was looking at 3 of the Frog series cartridges available here on Audiogon.