I've always gotten a bad reaction from people when I say this but I still stand by it: when a cartoon has a memorable musical number in it, people tend to severely overrate the episode and consider it the best entry. I could list over a dozen examples off the top of my head but that's not the direction I want this review to head in. My point is that I consider this the best episode of the series and it has nothing to do with the song featured in it - even though it was a wonderful piece.
Lost in Space was artistic, the story was touching, and part of it was shocking to me. I never would have imagined that a Jeff-episode would have won me over so well. It's already been stated by numerous people but this episode was very imaginative. The characters and setting were creative and fascinating. The romantic plot was enjoyable - sweet but sad.
The thing that won me over the most was how Roger ended up being tied into it. I absolutely loved the "decider" episode and they took it to a whole new level with this one - the twist made me gasp. Brilliant script.