I think kabocha is supposed to be a bit dryer and sweeter than buttercups. But I haven't tried Bon Bon to see how it compares.

Maybe once your Bon Bons are mature, get a kabocha and compare the two.. then report back on the tasty results :)

I'm growing both this year to compare. If I get a crop, that is -- the dreaded squash vine borers. Beasts!

I haven't had a good kabocha in a while. Sometimes the ones at the market are excellent -- dry, flaky and sweet -- other times they're terrible, usually under-ripe.