I am currently in an extended phase where I have a strict floorplan of corridors and rooms[1] up and down my entire height of fortress. To the extent that 100+ levels down from my Z-1 farms (some exposed to the air, some purely subterranean) I have my magma workshops to precisely the same layout. The main and central staircase feeds up and down as it is able (except where caverns disallow and require a diversion to a separate stairwell spot) and in/in-between busy areas many more stairwells also exist. (My defence being isolationist, with deliberate pinch-points at the surface and limited cavern entry, and relying upon military mobilty to whichever lever-controlled entry/exit I am currently employing[2].)
Per level, usually dedicated to a particular purpose (masonic level, bedroom level, magma-industry level (a magmaduct level immediately below that) I sprawl. Much less efficient than a small-footprint highly vertical fortress, being still spread across a high amount of verticality (with much untapped spaces all along its height) but out to at least half-way to the edge (or further), on some levels, constrained only by whatever external works I am attempting.
I also tend to make my corridors 3-wide, allowing for a set of ascending/descending ramps (alternating, before and after each stairwell spot) to drill diagonally through my structure for improved speed of dwarf movement in game-time (although not improved speed of dwarven pathfinding, of course, in real-time).
Worst of both worlds, some might say. I wouldn't argue to much against that POV.
[1] These being interchangeable, but usually either 11x11, or four 5x5s in a square, or three-by-two 5x3 areas, all set within the same area. The main exception being archery ranges which extend across and through multiple squares of this type, necessarily preventing corridors across their route.
[2] Also useful for keeping from being harassed by enemy squads whilst caravans wander in and out, unaccosted. If they should chose to arrive on the side of the map that is not the one the enemy has arrived at, of course.