In Chicago, as well as most of the northern suburbs (and many west and south I believe) EMT is the "accepted standard" for most AHJ's. NM and "smurf tubing" (ENT) are prohibited in most municipalities, but many county building depts. consider them OK for resi use in unicorporated areas. Even RNC is frowned upon for anywhere but underground applications (resi) in many towns.
MC is often classified the same way as Greenfield / FMC, and only allowed for flexibility (motor / lighting whips) or for fished applications.
AC (BX) has become less than desirable as well in many towns.
In MA the accepted norm is MC. It depends on the location of course, but 90% of commercial buildings in this area have MC weaved throughout. You can tell a real quality job when it's in pipe or the MC is actually "installed" and not thrown in like loose rope. I have opened suspended ceiling tiles in new buildings and had 25lbs of MC nearly knock me off the ladder!
The company I work for uses EMT to the main J-Boxes and then whips out with MCC. In the walls we mostly use MCC unless its 3-way lighting or something special. Everything is strapped per code and we try to do nice clean runs with the MC. As a courtesy to the next guy, all our MC is at least 12" above the grid.