One of the best shows available
One of the best ways to judge if a show is overstimulating is to stare at it for a moment and count how many seconds each shot lasts before they cut to a new one. Over time, television has moved towards faster and faster cuts. Some shows try to resist this urge and hold shots for slightly longer than their contemporaries, thus making it more suitable for young, developing minds. Little Bear is one of these few shows.
To add to that, the characters also live quiet lives in the woods, away from cars, standardized tests, and supermarkets, so this gives it a bit of a dreamy, vacation quality that is relaxing for adults to watch with children (as opposed to some of the repetitive, annoying options out there).
While not as explicitly educational as other shows, Little Bear learns various lessons and interacts with many personality types, but no one is overly villainous or cruel. It is mostly focused on creative exploration or problem-solving, and I love that the characters all live in harmony with one another despite no one being perfect. They also show characters of all ages/genders interacting with one another in a way that isn't often seen in American children's television, which I think is healthy and important to model for a proper sense of community.
Little Bear is not very safe with his fishing rod. Fishing is a big part of the show (his father is a fisherman) and in one episode he is swinging it around in the house and hooks his mother's skirt! In later seasons, a new character is introduced, a monkey character who is an unabashed trouble-maker. There is also a strange line between which animals are sentient, and which are food. They converse with a frog and a snake, but regularly kill fish. In one early episode, Cat makes a joke about eating duck soup while Duck is in the room. This is something younger children may have questions about.
Despite whatever minor grievances, Little Bear is one of the best shows around, and is suitable for a wide audience. The adult characters are particularly well-rounded and likeable, and the Canadian version of the show is available for free online.