I used Go Launcher EX for a very long time - excellent customization, lots of add-ons available, and regular updates. Over the past few months, though, it's gotten a bit laggy and they're being more aggressive with pushing their themes and other stuff. The Christmas animation was cute once, but the inability to turn it off really pushed me over the edge! Their version of the App Manager never really worked (nor did I ever understand why it was even necessary) - it just added extra notifications without any benefit.
So, when Nova Launcher came up a while back in the 25 Billion Downloads sale, I grabbed it. I recently made the full switch because it has most (not all, but it's close) of the functionality and customization, and is MUCH faster. Sticking with Nova, at least for the time being.
+1 with B360155 that Apex is good but very similar to Nova. Atom looks intriguing, so I'll give it a shot in the near future...