I was an Enlightenment user from 1998-2007, but have since dropped it for Compiz (well, Beryl). Unfortunately, KDE and Compiz don't work very well together on recent Ubuntu versions. I've never liked GNOME, don't like the direction of KDE 4.x, and am half-expecting a Duke Nukem Forever 2 before a bug-free Compiz. I'm looking forward to trying a final release E17. Hopefully, it will have all the features I want, like better physics when I move programs around and rotate my desktop "cube" (or pager) and a great media player.
I expect this will be released in the 2H 2013 through 2014+(+++) timeframe. IIRC, 3 years ago, they were hoping for a Christmas 2009 release. Their last roadmap (last modified 05/21/11 12:09:00) expected an Alpha release in September 2009, then December 2009, then March 2010. I still haven't seen an Alpha release. I could be wrong, and there may be some release candidates (if they do more than Alpha/Beta) or even a full release as early as this November/December. Development will accelerate as things have been finalized (no more massive rewrites or foolishly redundant projects) and a release manager is brought in, but I think that's pushing things a little, especially if you consider their lethargic speed and aim for zero bugs.