jroc is always a good voice of reason, and generally has sound advice. as he said, it depends on your personal needs and uses. i have the GNex, and couldn't be happier. i've read quite a few posts from people complaining about the GNex, and what a POC it is - but that just leaves me scratching my head.
i use my GNex a ton, but not much as a phone - primarily data. if you spend the majority of your time making and taking calls, i still gotta give it up to Moto - the call quality on those devices is almost unparalleled. that being said, i live in a metropolitan area, and have never had much of an issue with call quality/reception on the GNex. (if Sammy ever comes close to matching Moto in call quality, it will probably rule the smartphone world.)
As for battery, i recently purchased the 2100 extended battery, and i'm getting about 14 hours (+ or -) a day with moderate to heavy use (again, mostly data). and, that extended battery is virtually unnoticeable as far as changing the thickness of the phone. for your use, you might need the whopper battery in the Maxx...?
the biggest advantage of the GNex, IMO, is the modding and ICS. i unlocked and rooted my phone right away. i don't do much rom flashing (certainly not to the extent i did with my OG), but i do like the ability to flash various mods and tweaks. with the Moto bootloader, you certainly can't mod and tweak to the same extent you can with the GNex. so, if that is important to you, it's hard to argue against the GNex.
as i said, i don't do much rom flashing currently. and that's primarily because, for me, stock ICS is pretty darn functional. imo, it is head and shoulders above GB. as history has shown, Moto is a little lagging in updating the OS versions. if that is important to you, then the GNex is a solid choice.
probably the biggest indicator to me, personally, of how nice the GNex is is the fact that i don't spend nearly as much time on the forums drooling over the next device coming down the pike. spec wise, the GNex is right there with about every device out there (altho you can quibble over certain specs), and it is just a buttery smooth beast! i'm not advocating over the Maxx, as i haven't spent much time looking at it. I have been a very long-time fan of Moto, and after the OG, never thought i would own a device from a different OEM. but, Moto kinda soured me (hopefully that changes with Jha getting the boot), and i've been perfectly content with the GNex.