I was wondering your motive for the question. Unfortunately it appears you may have an aversion toward gps or automatic control? I know, as I stand accused and am labelled here as having an aversion and being anti-gps. I used to phrase things like ..."I have no use for auto-steering". Now I try to phrase it as ...."if it pays a return, I will make the purchase". They both refer to the same thing from my angle, but not other's viewpoints.

Likely 99% of the replies you will get, will focus on the mechanicals like fatigue or strain on the operator. They may also focus on the luxury of automatic controls.

 I look at it from an efficiency possibilty standpoint. It is a tool. If I can put into play a more efficient method of cropping using automatic controls, and make it pay, I will do so. I am working on that now in fact. But it will have to pay a return for me to make the purchase. Right now, I do not need auto steering in the combine to keep a 30' header full to the last inch. If I change systems, auto-steering may become a requirement. I do not experience any fatigue or strain at the end of the day. But that is me, not the rest of the world.

 Some may be able to put a slightly less familiar operator in the cab if they have automatic controls, having less risk, allowing the owner/manager to focus more on management for the day. GPS, auto-steering, automatic controls etc., is not always about the operator of the equipment, it is also about the management possibilities. I feel it is important to keep your mind open to the possibilities, and not always focus on the current need. It would take hundreds of men and shovels to do the work of one small hydraulic excavator. Which would you rather operate?