I am using the neo2 keyboard layout at the moment. I made my transition not-so-long-ago, november 2014, mostly because I read how qwerty was designed AND BECAUSE OF CAPS LOCK. Neo is a layout optimised for the german language, and it has also some quite interesting ideas about how a layout should be organized. For example, it replacse caps lock with a layer for special ascii characters like _[]^!<>=&\/{}*?()-:@#$|~`+%"'; (okay, I admit it, this was the whole layer). I like it because I can understand how it was designed and I learned touch-typing with it. Learning it was painful but worth it. I haven't measured my speed yet, but I feel very comfortable with it.

Website: www.neo-layout.org