I tried natto on my recent trip to Japan. My wife's father ate a norimaki with natto in it by accident ( he thought it was tacuan ) and looked all weird and disgusted. My wife and her sister told me how disgusting they thought it was, so naturally I had to taste it...how bad could it be? I have enjoyed most other japanese foods, so in it went. And I must say, that natto is absolutely disgusting! I felt like someone took a dump in my mouth...yes, that bad.
This was at my wife's family's house, so I had to eat it, and I just managed to avoid throwing up by washing it down with a large amount of beer. How embarassing it would have been if I had puked all over the table.
I'll recommend anyone to try it though, and I also forced the wife to have a taste, after I found out that she never tasted it before, because she found it too disgusting. Who knows, you might like it.