Also known as the taschino (little pocket), the barchetta (little boat), a hand-made breast pocket is easy to spot.
The first giveaway is the presence of a micro zig-zag stitch or straight stitch along the edge of the welt- this has been done by machine. A hand-felled pocket will have no visible stitching along the edge, and may have a row of pick-stitching about 1/4″ from the side.
The second, more subtle clue is that automatic machines can only sew the welt on in a straight line- many tailors will give a very subtle curve to the seam of the pocket- this is supposed to more gracefully follow the curve of the chest but also help prevent the pocket from gaping open.
The hand-made pocket is clearly more attractive as there is no visible machine stitching, but other than aesthetics, can it be considered superior?
You are not likely to stress this pocket so the delicate hand work is in no trouble of coming apart. There is no performance benefit either way- it is just more appealing when done by hand.
Check here for the more pockets: Part Two