The pentatonic scale does not imply equal temperament between the five notes. The "good-sounding" pentatonic scales use very simple harmonic ratios, for example 1, 9/8, 5/4, 3/2 and 5/3 for the major pentatonic scale. In the equally tempered 12-note octave, these roughly correspond to the first, second, third, fifth and sixth. An equal division of an octave into five notes doesn't yield as harmonic results.

That said, 5-EDO sounds good in my opinion. Not very harmonic, but somewhat resembles the scales used Gamelan music.