Being one of the few who have actually ran both, the 820 will be easier with change of pullies, vs. chains and sprockets.
The 820 is also in my opinion more effiecient at getting the power to the ground and much more durable.
I used to change/break keys in the 700 on a regular basis with a single cylinder. With the 820, that was a thing of the past.
Even with stout v-twins, they were changed once a year, only as maintenance.
Unless forced by rules or gunpoint, I would never consider using a 700 again as long as I could obtain an 820.