floor first will allow the cabinets to sit on top of the floor so that futur removal/replacement will be easier. also, when the floor is installed first, it is easy to install the doors with the proper clearance above the floor. if doors are installed first, it may be necessary to trim the bottom of the casing and doors for interior, and the exterior jamb may be below the level of the floor creating problems with opening the door.
JMHO
Carl