It's running Android 4.1 though, didn't 4.2 introduce a lot of changes under the hood to boost Android performance? I presume 4.3 did too which the G launches with.
How the G beats the Nexus 4 though is confusing me as for raw grunt the N4 should be a good bit ahead since it's a quad core Krait with higher clock speeds to boot.
there is between a 5-10% boost in quadrant from 4.1 to 4.3 in benchmarks from the Galaxy S3 and N10 (ones i could find the difference)
The Moto G has a 50% higher score then the Xperia M in quadrant. Its clearly better then that chipset