It's got a very iTunes-like interface, and seemingly can do all that Suitcase does, as well as clean font caches, provide detailed font info, etc. The only catch is that you also get a Store icon where you end up at Linotype's online font store, which also looks somewhat like the iTunes Music Store.
[robg adds: I tested FontExplorer X this morning, and it seems to work well, though there's a fairly scary disclaimer up front -- this is a Final Candidate release, and you may lose your data, don't use on a production machine, etc. After making sure my backups were current :), I proceeded to use it anyway, without any apparent ill effects. However, I'm not a heavy font user, so I can't comment as to whether this app completely covers Suitcase's functionality.]

