To a layman's eye there's nothing particularly noticeable about the craftmanship in this photo because the custom work is meticulously done to conceal the too-many-to-count quirks of differing window widths; mis-aligned windows horizontally and vertically, and multiple window frames, all on different planes of the interior wall.
All these oddities required over thirty custom, hand cut, shims tapering from 1/4" to nothing to 3/8" to nothing over a length of 25"-30", and simultaneous adjustment of the casings.
If any of that makes any sense.