Ok....back from my errand.
This comparison between 950 & 800 is a worthy discussion, but there is always so much "wind buffeting" as Itsatdm has said, every time the discussion is held.
I agree with your points, DesertSurfer, about the disappointment that BMW, being who they are, seemed to come up short of perfection in a few areas....maybe several areas. I don't know if that was driven by cost savings, short sightedness, or quite possibly, a different "end" in mind.
In reality, 75% or more of the 500lb class Adventure bikes probably never get further from a dirt road than a tent site. Maybe they shouldn't. Then, along comes a few riders like you and me who have visions of something much more sinister....
And, so it begins.
It sounds like you haven't had any decent saddle time on the F800. If not, you're frame of reference is limited in this case, to a spec sheet and imagination, plus feedback from others who have. Wish we could ride together, swapping bikes for some real testing, as it seems we do similar things and have "setup" for it. That would be fun.
My carb'd '04 950 was super smooth off bottom.....WAY more than the FI 990, for obvious reasons. That made it significantly better in the dirt, than my friends 990. This was critical due to the exponential power delivery of that motor. I've not ridden a more recent 990, so I don't know if or how they might have fixed that issue....probably not. Most FI bikes (at least in the early years) had very snatchy take-off from idle, at least those made for the dirt, that I've experienced.
What captivated me with the F800 was the way the bike felt and handled, coupled with the linear smooth power delivery. It was snatchy off bottom, but that was easily fixable. The frame geometry and weight distribution was magical to me. Floats effortlessly responding to my inputs easily, turns on a dime, and has amazingly good traction due to all of that. It really surprised me.
The 500 lbs bike felt more like 350 between my legs. Putting the tank beneath the seat was a superb idea, I think. Weight distribution seems to be about 50/50 front to rear. The bike has a very weight neutral feeling to me when in motion....relatively speaking.
I discovered a "platform" that I had been looking for....something hard to define, but easy to "feel". The important things were there....which were not easily altered. All the other things I wanted, could be easily altered (though some expensively). I didn't find that on my 950, and it was disappointing. The difference: I rode on my 950, while I feel one with my 800. It somehow pushed my button.....satisfied an inner yearning. Had nothing to do with brand image or loyalty whatsoever. Heck, I had never even ridden a single BMW in my life, before my F800 test ride.
Either bike could be ridden in stock form indefinitely, as designed for the masses. If someone wants a better 500lb whale for the dirt....right out of the crate.....the 950 is the way to go. That has been clearly stated by many in this Thread, so it doesn't need to be passionately defended any further.
BUT my F800, after my personal mods, has become a more lethal weapon for me, than my 950 ever was. Hands down, no contest. Its been an interesting project. I too am 50 yrs old, and slowing down a bit with each galactical rotation. Maybe that has something to do with it....I donno.