Both feature a bunch of kids experiencing ghostly adventures in a small town. However, do not underestimate these shows simply because they cater to kids. In their own way, both shows serve their purpose in scaring the audience.
Kaidan Restaurant makes use of the slice-of-life story-telling which lets your imagination run freely (and against you). Ghost Stories uses scary animated scenes, which despite the quality, works pretty well.
In Kaidan Restaurant, the stories are narrated by the friendly spooks themselves while in Ghost Stories, the kids are aided by a reluctant supernatural sidekick. Yet, the audience gets drawn into the tales anyway.
Stories are told in that same calm manner, like typical Japanese ghost storytellers do. There is little drama in the narration which is good, since it lets the anticipation build up slowly and the mind gets to run around freely on its own.
That's how I like my ghost stories.
However, in Ayakashi, the stunning visuals speak for themselves. In Kaidan Restaurant, your imagination is merely aided along by the friendly subtle scenes which comes across as creepy rather than full-blown scary.
Both are about a bunch of kids interacting with ghost's in one way or another, Yokai watch is a bit more goofy about it though.
Both are more of a collection of short stories rather than a whole series as in they both focus on random ghost's for an episode rather than have some sort of big story.
Both have a weird white ghost blob thing who is sorta the mascot, in Yokai watch Jibanyan is also the mascot and it's often said how everyone likes him more than whisper in the show but personally i prefer whisper.
Linked by Occult and Funny
Kaidan restaurant typically would have 3 short occult stories per episode:
The 2 main dishes vary in style and are often quite funny and a little bit scary.
The last dessert is often more scary. Though kids oriented, the stories remain interesting for occult fans.
Seikimatsu Occult Gakuin is more `gaggy` with better animation and plot.
It has a lot of ideas in one main story: black magic, time traveling, supernatural power, aliens. Stuff happening in 1999 will be affecting human's future in 2012.
I would approximate the ratio of entertainment to be 3:7