Planet of the Giants is a fine example of 60s Doctor Who. Some of the early serials can drag a little, but at just three 25 minute episodes, there's just no time for the plot to sag.
The effects are fantastic, especially considering the tight budget the crew were working to. The physical effects, like the giant ant and the fly are well realised and the sets (briefcase, kitchen sink, lab table) are simply fantastic.
The main cast are on fine form, especially Hartnell, who exudes a childlike fascination throughout the whole story. The guest actors all do good work, too, even if their plot concerning a deadly new insecticide isn't really as exciting as the adventures the miniaturised crew.
At just $15 (at time of writing), this is a bargain, and would make a great addition to any Who fan's collection!