U.S. Navy plans to equip future aircraft carriers with electromagnetic catapults took a big step forward on December 18th when, for the first time, an electromagnetic catapult launched an F-18E (from a land base equipped with the test version of the catapult). Earlier this year, tests had been put on hold for a bit, while software problems were fixed. The mechanical aspects of the electromagnetic catapult were pretty much solved, but the test model the navy was working with has been having some serious problems with the control software.
The plan to put electromagnetic catapults into the next carrier (CVN 78, USS Ford) cannot be dropped, because the Ford is under construction, and a massive (and expensive) redesign would be needed to make room for the bulkier steam catapult.
EMALS (Electromagnetic Aircraft Launch System) is preferred because it puts less stress on launched aircraft (it moves the aircraft forward more gradually), requires fewer people to operate, and is easier to maintain (not much plumbing, fewer mechanical parts and lots of sturdy electronics). The gentler treatment of launched aircraft now means that smaller aircraft can use the catapult.