Favourite Ranger: Tanya Sloan, The Yellow Zeo Ranger
Favourite Villain: Archerina
Favourite Episode: "A Mystery to Me"
Least Favourite Ranger: Rocky DeSantos, The Blue Zeo Ranger
Least Favourite Villain: Prince Sprocket
Least Favourite Episode: "For Cryin' Out Loud"
When a band of robotic conquerers known as the Machine Empire set their sights on Earth, it's up to the Power Rangers to stop them. With their new powers and a new Ranger, they are re-energized and ready to take on their biggest challenge yet.
As iconic as Mighty Morphin Power Rangers was, its follow-up Power Rangers Zeo proved itself to be of a higher quality in both storytelling and tone. Where the original series struggled to find its identity, Zeo finds a happy medium between camp and seriousness. It borrows almost exclusively from Chouriki Sentai Ohranger, which saves it from disconnects with costuming and odd Zord usage. Aside from that, Zeo isn't quite as scattershot as its predecessor and should be applauded for taking its time with its narratives. There are numerous overarching plots in this series, many of which help character development.
Two of the major storylines for this series include the introduction of Tommy's brother David and the mystery of the Gold Zeo Ranger. The latter becomes a recurring plot point that unfolds over the course of several episodes. The decision to keep the identity of the Gold Zeo Ranger secret was brilliant and enabled the writers to include several red herrings. This keeps the audience guessing, although the eventual reveal was a touch underwhelming.
Beyond the improvement in writing, Power Rangers Zeo featured stronger characterization in comparison to the past season and a half of Mighty Morphin Power Rangers. Tanya Sloan, Aisha's replacement as the Yellow Ranger, is a standout. She's smart, she's funny and she's a pretty darn good singer. In fact, Tanya's singing talents were utilized in a couple episodes. Similarly, both Kat and Rocky receive more attention than they previously had. Kat is characterized as a perfectionist and athlete who harbours secret feelings for Tommy, while Rocky is seen as much more impetuous and immature. The Zeo line-up may not be quite as distinct as the original five from the first series, but there's a chemistry there that makes them believable as a team and as friends.
Even though the heroes are the stars of the show, the villains prove themselves to be worthy of praise as well. As a whole, the Machine Empire is much more menacing than the more generic Evil Space Aliens led by Rita and Lord Zedd. The designs are a little clunky, but their oppressive regime and distinguishable personalities make up for that. Where Rita and Zedd's bunch were portrayed as bumbling fools, King Mondo and Queen Machina have much more capable help. From the bratty Prince Sprocket to the scheming Prince Gasket, there's much more diversity with the antagonists this time around.
Taken as a whole, Power Rangers Zeo is arguably of a much higher quality than its predecessor. The writing is tighter, the characters are distinctive and the tone is much more cohesive. Broken down, there are several subpar episodes that are questionably written, but the overall aesthetic of the series allows the franchise to take on a more layered way of telling its stories. While it may be often forgotten amongst the other entries in the franchise, Zeo was groundbreaking at the time and it really helped to continue the legacy of the Power Rangers from remaining stagnant. For that, Zeo deserves more love than it gets.
(As a side note, I think the Zeo/Ohranger costumes are some of the best design-wise. They're pretty snazzy.)