things i hate about straight manual shifting, make it a regular truck, to a tractor....
when working on various projects and using FEL or 3pt hitch and working on a hill, or in/dirt muddy spots. and i want to barely move 1" forward or backwards....
trying to clutch, break, shift, turn, raise/lower FEL and/or curl bucket, give some throttle so ya don't kill engine/get over bump some. not really possible all at once, 2 feet, 2 hands, there is not another hand or foot to go around. at times not enough feet to go around when backing up to a trailer to hookup to.
when i am out mowing, i have various hills, and areas were grass is thicker / taller than other places. and the difference can be so much to the point that simply giving a little more throttle/gas will not work out. i need to jump down to a lower gear to get through the area. half the time i am on a hill. so as soon as i hit the clutch i am free wheeling down the hill, before i can even get the shifter moved over to next gear, let alone letting clutch out. and i just left a spot of grass i have to go back and re mow.
independt PTO and rear 3pt finish mower can help with above but...
there are various tranmissions out there, and controls for them "pedals to levers"
==================
a hydrostatic transmission, is a nice thing to have, i just wish more tractors would come with a "transmission temp gauge" and not simply a warning light if anything at all.
it can be much easier for new operators, to try drive at a much higher MPH, than what should be allowed, and causing the hyd oil to really take a beating in the friction department, causing oil temps to sky rocket, example if you try and lift to much with your FEL or backhoe. "relief valves kick in" so you do not go over the max pressure / lifting weight of the FEL and/or backhoe. same like doing of "relief valves" can be found in hydrostatic transmissions, but you can't hear them, you can't see them, and there is no sort of warning lights or gauges to go by :/ and that is were the hyd oil starts to over heat, and damage to seals, 0-rings and like start happening, let alone hyd oil / transmission oil taking a beat due to over heating.
other words unlike a straight manual transmission. instead of the engine bogging down to point you might stall the engine out in case you are in a wrong gear. the pressure relief valves inside the hydrostatic transmission might kick in. and not have any effect on the engine bogging down to point engine stalls out. but the operator of the tractor may never know, and nothing for the operator to go by. so novice to pro's alike are at a guessing game. until finally hopefully a warning light comes on for over temp transmission, given you notice you might have been operating in to high of a gear position.
=================
just stating "shuttle shift" is a bad thing, having a ""fully synced"" transmission. is the key. so you can go straight through to the next gear (up or down) quickly and easily, and hopefully by just pressing a simple joystick button on the gear shifter, and moving right into the next gear. and then for actual shuttle shifting another joystick button, on the shuttle shiftier itself. HST style pedals (rocker style pedals) it may mean just rocking the pedal forward or backwards vs using a shutle shift lever and joystick button on the lever.
the issue with above, you may not find SCUTS (sub compact utility tractors) and CUTS (compact utility tractors) that are fully synced transmission. and use "shuttle shift" as a marketing ploy. without telling you transmission is not a fully synced transmission. resulting in a straight manual transmission.
i mention joystick button above, some have a cable linkage from button down to location on transmission to engage / disengage clutch. while this is fine and dandy, the cables and linkages may need to be adjusted over time. and/or the button might seem hard to push or simply release. a joy stick button will have wires ran to a solenoid at transmission with a short linkage if not mounted directly onto the transmission itself. (most likely costs more doing this way) and for SCUTS and lower end CUTS. it is easier to do this with cable and linkages to come out cheaper for manufacture. but when ya get into larger tractors, and distances between operator and transmission happens, most likely the joystick button and solenoid come into play to make things cheaper / easier to install / manufacture and you start getting into joystick buttons vs cables and linkages.