I preferred the last 1/3 of it, with the heavy beats and it got a little darker than the start. I really enjoyed the whole song, but from before the bridge until the end, I loved it.
And yeah I really don't know HOW they picked OTR as single #2 when they had many better choices obviously. She'll release Run (probably) as the 3rd UK single NEXT MONTH so the performances of it could help the album's longevity and sales.