It's Davison's first story. His Doctor is regenerating and bumps around in a winning daze- synapses firing randomly- looking for his new self. We get to see some of the insides of the Tardis (it has a room full of cricketing memorabilia!) and visit the oh-so-charming-it-can't-be-true late medieval city state of Castrovalva. Escher is a source of inspiration, also Lewis Carroll. As with those two great artists there is a sense that we are getting baffled glimpses of a world that is larger, stranger, brighter than the one we know.
Davison is among the better actors to have played the Doctor. Perhaps the best of the "classic" era. This script gives him opportunities to demonstrate subtlety and range. His Doctor is boyish, charming, vulnerable, effortlessly commanding- and gets to do some mean impressions of his predecessors.
I don't care for Who when it goes all war of the worlds. Notice how, in my meanderings I have thus far avoided any story featuring Daleks or Cybermen. The stories I like are the ones that take us to places where anything can happen...