Chose the G2
I chose the G2 this weekend as it is a spec monster. The Nexus will offer the original android, which I have on my '13 Nexus 7 but all indications lesser camera, lesser battery, lesser screen size. I'm not a huge fan of the LG's UI but it's not a deal breaker. I moved over from the "Apple" camp this year and traded off a 4s for my G2. Now running with iPad 4th gen, new Nexus 7, and LG G2. Looking forward to rooting and going custom ROM on the G2; though I think I'll fiddle with my Nexus first - in case I break it; a more affordable piece of kit to replace.
Android has changed immensely since last I dabbled in it with the HTC Droid Eris; when I went to Apple the devices and UI were miles ahead, now that I've come back to Android the UI is equal / better and the devices are equal / better. The biggest plus is that the Android vendors don't tell you that you can only have a 4" screen and the fanboys don't bemoan how the app developers can't possibly match all sorts of screen sizes. I always found that a ridiculous argument in the Apple fanboy forums - hmm, yes you must be right that's why Android apps can't match all the screen sizes...