No, I haven't been there, but to my knowledge, it's only claim to fame is being a picturesque view of a tree-covered peninsula. It's pretty far from Osaka, being on the northern coast of Japan. Awaji Island is much closer to Osaka, but I'm sure Amanohashidate and Wakasa Bay has nice scenery... it's your trip, your choice.

Have you tried searching for Youtube videos for these places? Here's Amanohashidate: YouTube - Kyoto - Amanohashidate and here's Wakasa Bay: YouTube - 蘇洞門めぐり , YouTube - Wakasa Bay Beach - snorkeling, cliff diving, fun!


Awaji: YouTube - Whirlpools between Awaji Island and Shikoku Island

Hrmm, based on those videos I think Amanohashidate looks more interesting, even if it is further away. At this point I think I'll play that day by ear - I haven't really left myself a full day in Osaka, so if it all feels like too much I'll probably just hang out with my friends there or think about going to Awaji.