I can shed some light on the gear drive Kubota, from the point of view that it's essentially the same tractor as my L3400 with different bodywork and a few more horsepower. That may not be 100% accurate, but they are very similar.
Pros- proven design, very comfortable to operate, great steering and handling.
Good power and fuel economy, really nice engine, easy starting in cold weather.
Excellent brakes.
Cons- 3 point hitch MAY be jerky when raising small increments. Try it with something attached (rotary cutter for example) and see if you can live with it.
Gear shift is very long, interferes with legs and boots getting on and off if you're in 2nd or 4th. I shortened mine about 5 inches, much better now.
Loader joystick is also very long, hooks on jackets, makes it very tricky getting on from right side if you want to. Again I shortened mine about 6 inches, helps a lot.
Diff lock pedal is in the worst place imaginable, under your right heel. That foot already has enough to do with the throttle and brakes on the same side. HST has it under the left heel, where it belongs. Someday I'll look at moving mine if I can.
ROPS rattles when up, I added wooden wedges to quiet it down, they work well.
Turn signal lever hooks on pant legs, I cut the long end off to cure that.
Check to see if a hydraulic rear remote "kit" (pre-bent pipes, valve, fittings, and quick connects) is available now for the L3800 if you foresee a need for rear hydraulics. None was available for the L3400, I had to build mine from scratch.
Suspension seat may be sticky. I freed mine up (it was stuck solid from new), and it works great now.
The clutch effort is a little high, and "hung" pedals would be an improvement over the lower pivot ones the L3400 has.
It may seem I've found a lot of cons, the L series is a good tractor overall, but they aren't perfect. Not much is.
If you're buying one, you deserve to know what others have found issues with, and those are mine. Some were easily addressed, others are more problematic.
Good luck!
Sean