I think he is comparing the straight -with - an - angle loader arm compared to the more recent curved ones. I haven't seen any true straight ones on small tractors, only on some backhoes and payloaders.
I have the non-curved loader arms; I have not had the opportunity to try a curved profile so I am not sure what is better. I suspect that there would be very little difference when attaching buckets, but better visibility when working?
This is my "straight arm"
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vs a curved one (courtesy of another member here - I borrowed this pic for ideas on a cab for mine)
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