I've tried a lot of saddles, but the ISM Adamo Breakaway is the only saddle that I have ever been able to ride long distances on. That makes me a fan. However, everyone is put together differently, and maybe the Adamo saddle style just isn't for you.

Before you put yours on eBay or take it back to your LBS, try tilting the nose of the saddle up or down a little. That made a difference for me. Also remember that even ISM says that some riders experience pain from putting so much pressure on their sit bones. It happened to me, but after a few rides it went away. (See their FAQs at http://www.ismseat.com/faq#answer-4) Also, you may want to watch their fitting video at http://www.ismseat.com/how-to-fit

Good luck!