Overwatch Beta Version is what Players will get on Launch

On the official Overwatch forum, players spoke with the game's director Jeff Kaplan and his answers were that the final edition of Overwatch will not be much different than the current beta we're experiencing now.

"The version of Overwatch you are playing right now is what the final version will look like when it's released live after the announcement" says Kaplan, adding that he doesn't count bug fixes as something new, which is logical given the fact that the game recieves lots of daily updates.

He also commented the competitive gameplay that occured in the closed beta but now it's not available in the open Beta because of the ton of great feedback they've receieved on how to fix the system as thoroughly as possible. He said that it was a tough decision to do that since it would've been good to have that same feature active in the open Beta, as well as on Launch but they didn't want to sacrifice the quality of the game by pushing something that isn't up to the standards.

Kaplan said that based on feedback they've been given from testers, they concluded how game modes should be worked on in the future and after that, released when fully perfected, adding that he worked on "tons" of new content which will be available after the release of Overwatch. Overwatch will also be adding some post launch features and content that will make this ‘a pretty amazing summer’ according to Kaplan.

Players asked about what will happen with the progress they've made during the beta phase were given the answer to that question:
“No. All progression including skins, rewards, levels, and stats gained during the Open Beta will be reset at launch. This includes any progression gained during the early access portion, as well." was the statement from Blizzard.

You can pre-purchase the beta from the Battle.net store now to enter and try the game before it's release.