TxFarmer,
Let me start by saying I am in no way trying to change your mind, but I would like to comment on a few of the things that you said that were running though our minds before making the same decision. I am in no way knocking anything, just offering my experience.
We ran JD conventionals (I probably have 3000 seat hours and would hate to guess the "wrench turning" hours) from a 95 through the 9610s and demoed a 9650 before switching to Axial Flows (probably 1000 seat hours and still hate to guess the wrenching hours). the decision was long and difficult to make to switch to something we knew nothing about, but we kept leasing/demoing them and they consistently out performed our conventionals.
The comment about a rotor w/2000hrs looking like a walker with 4000hrs is probably in reference to STS's vs 96xxs. I have no experience with STSs so I can't comment on them. I do not believe that is the case comparing a 9600 to the same vintage AFs. I can say with certainty that in our conditions a AF with 3500hrs on it is no more wore out than an conventional with 3500 hrs on it.
The conditions here can also be less than optimum as well. The AFs we have now will consistently provide a faster ground speed and a generally better sample. The best way I can describe it is they seem to be more forgiving, or have a larger sweet spot. I find myself "tweaking" the setting much less often than I had to with the conventionals. With the conventionals I was constantly fiddling with them trying to get the sample cleaned up and keep the losses acceptable while maintaining a respectable ground speed. By far the hardest crop we thresh is lodged green stemmed irrigated soybeans, which can make threshing weedy milo look like a cakewalk. The AFs perform every bit as well as the 96xxs we ran, and with an AFX rotor, better, all while making a cleaner sample. We were scared to death of a rotor due to this crop, but I can honestly say that a conventional does not handle tough weeds or green stemmed beans any better than a rotor. Actually, I have spent WAY more time underneath the feeder house digging out a cylinder than I have digging out a rotor slug (only slugged a rotor once in green stemmed beans before the header got shined up. It was by far worse to unslug than a cylinder).
The AFs are running a little cheaper in yearly repair bills than the JDs were, and in my opinion most things are a bit easier to work on. There are far less belts/bearings etc. I could come up with a fairly long list of things that could be beefed up on the AFs (mostly sheetmetal) as well as I could for the conventionals.
What it boils down to is what you are comfortable with, which has the better support etc. Where we live the JD dealer seems to be more interested in selling mowers and compact tractors that ag equipment. I don't think the employ anyone who can set a combine (never seen any of them come out to help us set them). The CIH salesman was out the first time we harvested each crop with our AFs the first year, and is out at a moments notice if we have trouble (which we don't really after the first year we got the hang of them). That was a big factor in us making the switch.
There isn't a darn thing wrong with a 96xx and they will do fine, I just thought I'd try to provide some (somewhat) unbiased opinion on our experience with both.
Best of luck whatever you decide!