There are variations, but in general, a Technika has back movements and a rotating back, more front movements, and triple extension (as opposed to double for the Graphics). Some of the Graphics with top mounted rangefinders can use cams for different focal lengths, but most have a rangefinder that can only be calibrated for one lens at a time, if they have a rangefinder. Technikas can have cams ground individually for each lens, so the rangefinder can be more precise, particularly for shooting at wide apertures and close distances.
Speed Graphics have a focal plane shutter, which a Linhof doesn't. A Crown Graphic is lighter than a Technika, so if you can live with a rangefinder that is calibrated for one lens, it's a more handholdable camera. Of course for the price of a Technika, you could buy several Crowns and calibrate each one for a different lens.