JD guys are finally getting a chance to worry about rotor belts now, huh 270, since the STS came out.
The hp was always the limiting factor on JD machines here in the south also. 55, 95, 7700, 8820, 9600, CTS, 9610, CTS 2, 9750 and now the 9860. The combines would always take another 50 horsepower in a rice field and experienced fewer breakdowns (hydrostat not withstanding) than if they were left underpowered because a combine with the increased hp was not as apt to buck, jump and choke up like one that was underpowered. The downside is when one that's turned up does choke, reverse it and just get off and dig it out instead of reversing it over and over and trying to get the plug through the machine.
If JD would build a combine for a rice farmer, test it in Arkansas and Louisiana, build it strong enough and with enough horsepower that it could cut standing rice with a 30 ft. draper whilst booking 3 mph, dumping 4 bushels per second on the go and cutting ruts 2 ft. deep... there wouldn't be a need for any other manufacturer to build combines. A machine like that would cut wheat so fast that you'd have to get I Robot to drive the freakin' beast. I'm talking about so much power you could cut down corn with a flex head and enjoy it, get off the combine at the end of the day feeling like you just took a shower with Irish Spring.
Only problem with that is they'd charge 500,000 dollars for it.
Makes me love that old 7720 under the shed. It ain't no speed demon but it's been paid for since the 80's and it can still get the job done.
To answer the original question.... I'd get the 9760's