I had a watch of the extended trailer earlier tonight. It's certainly looking enjoyable. I just hope the show hits the ground running (heh!) since I almost gave up on its sister show Arrow part way through series 1 thanks to the seemingly endless soap opera aspects to the story. Luckily I didn't and Arrow has become one of my favourite shows on telly right now.
Executive producer Greg Berlanti has said that The Flash will have more of a sci fi feel to the show were as Arrow has more of a crime feel to its show.
The pilot was wrote by Geoff Johns Chief Creative Officer of DC Comics, his wrote for the Green Lantern, The Flash and Aquaman comics. He also wrote a few Smallville ep's "Recruit", "Legion" and feature-length episode titled "Absolute Justice". He co-wrote the teleplay for the episode "Muse of Fire", featuring the Huntress, and fully wrote the episode "Dead to Rights."