3 speed auto... drive is direct. Probably better on the highway, more responsive than a 6 speed. Actually, turn off your OD... now you have the 3 speed automatic.
With the 4 speed automatic you might need 4.88s, thanks to that 0.69 OD. The 3 speed offers almost the same cruise rpm at 60mph with 3.55.
3 speeds go back to the days when an engine had a broad power/torque band. Todays 6, 8, 9 speeds are designed to keep the engine in a very narrow, computer controlled power band. And they deliver excellent fuel economy and outstanding horsepower. But to maximize all those benefits they need computer controlled automatics,,, hence you can no longer by a pickup with a clutch... well maybe one. The lowest power Cummins offers a clutch.
Which is better? My favorite tranny has 18 speeds... but you are always shifting. You have to love driving. The old CJ with a 3 speed, 304 V8. Power from 800rpm. A bit more power at 4000rpm. But a blast to drive. You only had to shift if you remembered to.
I have often wanted an old TJ or YJ with the automatic. Or another 3 speed CJ.