Blizzard recently made an announcement regarding Overwatch's competitive play. Game director Jeff Kaplan has announced on Battle.net's blog a few days ago that the mode was disabled so that improvements could be implemented:
"We worked extremely hard to get Competitive Play in the game for Closed Beta. We've been reading feedback from the community and taking it all to heart. As a result, we've temporarily disabled Competitive Play for Open Beta so that we can rework the system and make it better."
At the time of its disabling, the competitive play mode offered players five tiers: Challenger, Advanced, Expert, Master and Heroic, each with five divisions. Once players advanced in rank from the first to fifth division, they would rank up a tier. The top tier -- Heroic -- is like Hearthstone's Legendary rank. Once a player reaches that tier, they are be able to see how they compare to other players worldwide who are also in the Heroic tier.
A recent update also added rewards for progression, such as legendary character skins. It also added punishments for players who frequently would quit matches. Initially, players will receive a warning from Blizzard. Repeated offences result in an EXP penalty.