I have both, and will likely keep both, though the 9 gets used more. I even have a couple of pics of them together:
The handle was too thin for me (as mentioned by others) so I wrapped it in paracord, making a lanyard at the same time. It's about right in girth now, but the paracord is as hard as steel when it's wrapped tight like that. Completely eliminates any cushion from the ribbed Neoprene handle, and isn't very comfortable to use like that. I have considered unwrapping it, but my hands are big, so that would likely make it useless to me.
I read everything I could find about D2 after seeing several concerns about its brittleness etc. What makes a blade brittle has as much to do with its Rockwell Hardness Rating as it does with the base metal. Not all steels have the potential to get to the same hardness rating. D2 has very high potential, but it is the heat treating that determines whether or not it reaches that potential. Kershaw didn't get anywhere near its potential hardness in their heat treating process. It's like one or two points harder than the BK9 (Outcast RCH= 60-61 - BK9= 58-59). For the most part, the brittleness of D2 has been heat treated out of the Outcast, while its hardness potential has been utilized to the fullest extent possible to balance between the two stats.
Now, the harder Outcast is a bitch to sharpen, but it's mostly about the time it takes. If you're decent at sharpening your Beckers, you can be just as good at sharpening D2, just be prepared to take more time with it.
I have three main choppers, the 9, the Outcast, and a Cold Steel Gurkha Kukri (in SK5, which is very similar in composition to 1095). My favorites (for chopping only) would be listed in the exact opposite order, the Gurkha Kukri first, the Outcast second, and the 9 last. However, the blade-shape of the 9 makes it more useful for my purposes. Batoning with either the Outcast or Kukri is difficult at best, and actually quite the pain in the a$$ with the Kukri. Draw-cuts are about equal with the 9 and the Kukri, never attempted it with the Outcast. I've done fuzz-sticks with both the 9 and the Kukri, but neither are particularly well-suited for that task. The times I've tried it, I actually ended up using whatever folder I had with me at the time. Weight category is won by the 9, nearly four ounces lighter than both the Kukri and Outcast, which each come in at 22 oz. However, that extra weight and their respective blade-shapes are important contributing factors in why they both out-chop the 9.
Bottom line, it depends what you want to do with your large knives. If chopping is what you want it for, you can't go wrong with an Outcast
or a 9, even though I think the Outcast edges out the 9 in that department. If you want more versatility, you probably want the 9. If you're planning on batoning with your knife, I'd say don't even consider the Outcast. Whatever, don't even take into consideration anything you hear about D2 being an inferior knife-making steel. Kershaw did a fine job of balancing the brittleness/hardness issue with their heat treating. I've torture-tested my Outcast
as a chopper, and it holds up just as good as any of the best choppers out there, and though it does take more time to sharpen, it also holds its edge longer than the 9. Everything's a trade-off. Decide what drawbacks you're willing to live with, and which strengths you demand, and buy either with confidence as long as you're realistic about what you demand from them. Or better yet, buy both and have all your bases covered!
Blues
ETA:

oooooooo
WANT!!!
when does that thing come out
and when they say carbon steel.... ?
Your last question there is why I wouldn't even consider buying that knife. I'm not a "steel snob," but I am a fairly knowledgeable consumer, and if a company doesn't think I deserve to know what I'm buying, they don't deserve my patronage. 'Course, it could be that they haven't decided yet what steel it's going to be, and if that's true and they announce a blade steel that I either already know a fair amount about, or that I can investigate and decide for myself it will suit my purposes, the design looks very attractive to me as well.