The WSJ story says, "According to one person familiar with the investigation, Capt. Chesley B. Sullenberger was able to keep the nose of the plane up while flying at a reduced speed partly because his aircraft's so-called fly-by-wire system used computers to prevent the jetliner from stalling, or becoming uncontrollable and falling out of the air. Preliminary data indicate that these computer-controlled safeguards remained fully operational until touchdown, this person said."
The story also states that the emergency "ram air turbine" which provides a source of electrical power/hydraulic pressure when an aircraft's engines no longer work, also seemed to have worked as designed.
The "successful crash" results can also no doubt be attributed to the fact that Capt. Chesley B. Sullenberger was in command of the Airbus A320. If you were forced to chose someone to glide a commercial aircraft into ditching in the Hudson River, you would probably be hard pressed to find a better qualified pilot to do so. Not only did he have 19,000 flight hours of experience across different types of aircraft, but Capt. Sullenberger was exceeding well-versed in gliders.
Aircraft flight computers are extremely valuable in emergency situations, but as the Sioux City United Airlines Flight 232 crash of 1989 demonstrated, having a high-trained and experienced flight crew aboard is as, if not more so, important to a survivable plane crash.