Flex drive was the oldest. Originally made for Tamiya SRB but later modified for RC10. I do not think it was good.
Chain drive was middle. At least 2 versions here: (1) with a front ball differential, (2) with front one way.
The one in this photo was the last version 'MIP 410 Legend'. This one has front one way and rear slipper clutch. I have this one at home