That said, traditionally:
Naples: Scholte without the shoulder. The softest shoulder made anywhere. Either with traditional set-in sleeves and a little bit of wadding, or with shirt sleeves (the spalla camicia). Never any pad. Set-in sleeves might have a slight rope (rollino). Pleated sleevehead, resulting from the large upper sleeve and tiny armhole. Super high gorge. High notch, almost pointed upward. The bottom edge of the notch might jut out a little further than the top edge, enough so that you notice. Wide lapels, usually a little wider (by a few centimeters) than half the chest; typcially with substantial belly. Super soft chest, sometimes draped, sometimes not, but always quite full. Lots of drape over the blades. Nipped waist. High waist and button point. Front cut (sidebodies) rather than dart, to slim down the skirt. Open front quarters. Shorter coat than one would typically see in London. 3 button roll through preferred on SB. Patch pockets, if not preferred, then certainly quite common. The patches have a dramatic shape: very rounded, and much narrower at the top than the bottom. Deep side vents. Quarter lined is common. Also: lots of what can only be termed â€œostentatiousâ€ hand stitching. Any seam that shows will almost certainly be done by hand; e.g., the outer straight seam on a trouser leg will be a hand-picked lapseam, as will the center backseam and shoulder and outer arm seams on a coat. The lapels often have edge-picking AND another quarter inch hand-stitch. Trousers: at the hip, with reverse pleats and tapered legs. Sometimes the cuffs can be quite dramatically wide, e.g. 2â€ on 5â€™5â€ guy. I am reliably informed that most Italians hate suspenders, though there is a small Anglophile sub-culture in Milan and Naples that wears them. The most famous tailoring firm is Rubinacci (London House).
Rome: high, pitched shoulder, usually roped to some degree. Built up but not out; no extension, typically. Everything lean and clean, no fullness or drape in front, and as little as they can get away with in back. Slightly lower gorge and significantly narrower lapels. No vents or shortish side vents. A shorter and narrower coat than the Neapolitan. More true-3-button coats. Flapped or besom pockets, typically no ticket pocket. Everything is also â€œsmall.â€ By which I mean, SR firms have proportional formulas for how wide (say) a breast welt pocket should be on (say) a 42 coat. The Romans trim that down by 10 or 20%. The trousers are slimmer, straighter, and more likely to be flat front. This is basically the silhouette that Brioni popularized in the 1950s.
Milan: the top bespoke tailors are more typically â€œEnglishâ€ than those in the other cities. Not so much Scholte or A&S English, but the rest of SR without the armor. Sloped shoulder, but padded (lightly). Soft but clean sleevehead. Full chest, but no drape in front, or maybe a touch. More subtle waist. Lots of 2-button coats with deep side vents for suits, 3-button roll-throughs more common for odd jackets. Higher rise to the trousers; not quite suspender rise, but above the hips. Fuller leg, and more likely to have forward pleats. Overall, a more â€œroundedâ€ silhouette than the Roman, which can be bit angular and somewhat severe. A. Caraceni is the best. The Rome Caraceni makes this too, or something like it, but more often three button, with a shorter coat, and lower rise, slimmer trousers.