There's no comparo between a slushbox and a MT. I'd take the MT any day of the week.
I wish the AWD came with a manual, but we all know this is less than a perfect world.

I wish I had the MT,but I still love my G and for my commute, I absolutely needed AWD and I'm still happy with my decision.
This comes down to your needs. If you can live with RWD, get the stick.

 

At least one review does have the X as beating the non-X on a track.

Personally I would just take them out for a test drive which is exactly what I did. I found very little difference between my XS and the S that I took out with identical equipment otherwise. The X felt 'heavier' but performance wise I didn't see much difference but then didn't exceed 85 on the onramp with either one (did hit 85 though).

 

I think I'm gonna go rwd

 

ive driven the 08 6MT and i was not impressed at all. The manual gearbox SUCKS. At high RPMS the whole gear shifter shakes as if its about to break off. G37S Coupe is the exact same way. The whole manual gearbox shakes unbeargingly when driven hard. My brother has the 335i 6MT and its no comparison it goes into the gates much smoother, doesn't give your hand a workout no matter how hard you drive that car. I have the 08S in 5AT and i love the auto on this car. Very responsive. I wish when u hit the paddles to upshift they actually would w/o a delay buts that a diff point.

 

I can't compare the X vs non-X, but in general, I will say I prefer AWD.

Of course, I own a 6MT RWDer, so why listen to me? As for the gearbox complaints, I'm not a fan of the clutch's point of engagement, but I actually like the stick itself. And I've driven non-S automatics and frankly wasn't a big fan. The stick is actually one of the main reasons I bought this car over the MB or Lexus (what you get for the price didn't hurt either).

 

Previous '06 G35 MT owner. Awful vibration from the clutch pedal. Thought about it every time that I drove the car. Didn't mind the shifter buzz, though. Thought shifting precision was excellent. Short throws and very well defined.

Now own an '09 G37xS. Great car. *HAVE* to have AWD and nothing else came close to the performance of the G37xS other than the 335iX. Can but didn't care to spend the extra 10K. Would have purchased 6 speed G37xS in a heartbeat though if available, all MT flaws included. I do like the 7 speed with paddles but just different. Since I drive in DS manual 95% of the time, would prefer the quick shifts of a DSG gearbox but realize that's not likely to happen soon. Any tuners out there that can shorten the time of those gear changes in DS mode?

Also don't like the soft rear suspension of the G37xS, way too sloppy for my tastes. Eibach will be getting a call soon.

So, the net...a G37xS 6MT (including the brakes, quicker steering ratio, rear suspension, etc. of the G37S) and all would be perfect in my world.