I used to be a pro cabinet builder, still do some, at my own leisure. High end cabs do not have screw on raised panels on end cabinets, rather, the raised panel/frame are integrated into being the end, by itself. I used to use a local door company on large jobs, but quit that and do all my own doors and end panels now. Reason..the door companies will not pre-stain a raised panel edge before they put it in the frame. When the relative humidity changes and it's dry in the winter, the panel will shrink and you may see an unstained line on the edges of the raised panel. Seen this happen many times. This don't happen on high end cabinet doors/end panels. Also, some shops attach the drawer fronts to the drawers then stain the drawer front, attempting to keep stain off the natural wood drawer sides. This is cheesy. Drawer fronts get stained by themselves first, then attached to the drawer, then sprayed. Type of finish is another factor. Cheap lacquer looks good originally, but will not withstand a working kitchen long term (10 years). I, personally, use conversion varnish from SW. Expensive, but, like most things in life, you get what you pay for. I only use 3/4" domestic ply, grade A1. Anything else, you likely will have voids. And if you don't care about voids, fine, but at some point when someone slides a plate into a cabinet and the void is just under the veneer, and a hole appears, then, you can't say it's a high end cabinet. Also, like what was mentioned, no filler strips, dovetailed drawers (all 4 corners), undermount/soft close drawer slides for drawers and pull out shelves, taller/deeper end and corner upper cabinets, under cabinet lighting with hidden wires into dados, etc. These are just some of the basics of what I call "high end" cabinets. When I bid a job, the first thing I do is measure, but more importantly, if a wall is more than 3/4" out of plum in 8', I decline the job, as it's too much of a pita to mess with. Wall levelness is a big factor in getting everything to install properly. Someone can make a perfectly square/door-drawer fitting cabinet in their shop, only to "rack" it when they install it on an unlevel wall, and then all the sudden, drawers don't open correctly, sit un-level, etc. Same with a floor..if it is out of level 1" in 8', I decline it, too, for the same reasons. Sure, I can work around it, but, my time is better spent than trying to fix someone else's screw-up.