I think Zygons
is OK, it's not a favorite, but, it's also not in the bottom of the Classic era for me (Though, there aren't that many Serials in that small pit at the bottom for me
For a story about an Alien with Organic Technology, The Jon Pertwee story Claws of Axos
is better, IMHO.
ETA: Just finished Colony in Space
. Why is this story called Colony in Space
, anyways? They're on a freighter, then on Earth, then The Doctor is in a Moon Prison, then on Draconia, and then on The Dalek/Ogron Planet. There is no Colony in Space (Always mixes me up with Frontier in Space