Uchuujin MuuMuu

A great way to teach kids the very basics of how consumer electronics work, and perhaps provide some inspiration and confidence to fix and maintain their items later in life. For younger children who have only just started learning about electrons and magnetic fields in school, they'd likely benefit from watching it together with an adult, in case they have any questions or lack the background knowledge to understand even the simple explanations given in the anime.

There's a nice balance between the story and the educational parts, and it all ties in together seamlessly, which is likely to keep children's attention even during the parts ... that aren't meant to be funny. The art style is cute and colourful. The story and characters are simple. Both beneficial and entertaining for kids.

There are some darker themes present.
(SPOILERS:)
A war wiping out an alien race is mentioned several times, and at one point there is the threat of a spaceship exploding and potentially destroying the whole neighbourhood. At some points they go into a bit of detail about the aliens killing each other over the rights to land and resources. However, this is all presented in such a way that the vast majority of children who are old enough to understand the very basics of electronics, will not get scared when watching this show.
(END OF SPOILERS)

Sometimes the characters get hurt, but there is nothing graphic. Violence is very rare.
(SPOILERS:)
At some point, one alien cat is held in a chokehold by another alien cat while he is threatening him. This scene is mostly funny, but there is some concern that kindergarten-age children might find it so funny and harmless-looking that they imitate it on other children.
At another time, a man ends up with a hole in his skull from an alien abduction, but the audience does not see how this happens, and the hole in his skull is only shown in an X-ray picture from the hospital.
The show also assumes that the audience is old enough to know what is dangerous, and what not to imitate.
(END OF SPOILERS)

Not recommended for adults, as the humour and story seems meant to appeal to children. The explanations are too simple for an adult to gain much from them, and a 2-minute web search on each electronic device mentioned, would be more beneficial.

Edit: Unsure why this was rated PG-13, likely not harmful for younger children, especially with parental guidance. Personally, I would enthusiatically show this to any child who already understands that violence is bad, and that playing with electricity can lead to death, and knows that electricity works by electrons and magentic fields.