It's been very exciting for me. I picked it up in about a day, asked some questions, and am now easily doing things I couldn't before, and it just works.
Did you know Sequel's open bug-list is often at zero open issues?
Tried AR but it blew my mind that after all this time the support for CPK is still MIA? It's not about Opinionation IMO. Sequel has opinions. It also has features though.
DM had a few bugs. I asked about the particular relation I was trying to get working in #datamapper and Jeremy suggested Sequel would do it easily, pointing me to the test for it on github. So I tried it on a whim. And he was right, it worked.
Then I saw the documentation. It's beautiful. Seriously. Makes my eyes water just thinking about it.
That Sequel isn't the default O/RM for everything-Ruby just goes to prove there is no justice, and no Santa Claus. I'm not always 100% in love with the syntax, but the documentation, the support, the features, all that means so much more than wether I get to define properties for my models or not, and it's not obtrusive.
Oh, and disk-space is cheap. I appreciate that Sequel doesn't break itself up into 500 gems. That really annoys me about DM. There's no excuse for that outside of database drivers (and yes, that is absolutely my own fault; but it should get fixed...).