Xylon ROM 4.2.1 it's on galaxy Nexus root. Com that or paranoid android 4.2.1 they're the only 4.2.1 ROMS I know of both are smooth and really not bugs that I'm aware of I'd go for a 4.2.1 rom why go back down to 4.1.x when 4.2.1 is available all the new features in it are awesome too.
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