United and Continental merged both their reservation systems and websites over the weekend, which was essentially the last big step in their transition towards operating as one airline. As you might expect, there have been reports of some minor system glitches and delayed flights across the country today, but it appears that the transition has been an overall success for United. The successful merger of United and Continental also presented the perfect opportunity for Chase to launch a new version of its popular MileagePlus Card, which is now called the United MileagePlus Explorer Card. Here's a brief breakdown of the pros, cons, and my final take on how the United MileagePlus Explorer stacks up against its competition.