I'm going with the 366 meter length until absolute concrete evidence is presented otherwise and no the Blu-Ray picture will not suffice it was just an inflated image of the ship. Random quotes from various ILM staffers won't work either. A technical manual designed by the people who finalized the ship's design will do nicely but we know the likelihood of that coming to fruition. Their own movie contradicts what they say anyway.
Again I'll say... the size of the ship has NOTHING to do with the story being told. If the acting isn't good enough for you, fine. You hated the plot? Coolcoolcool. Directing not your cup of java? Kudos to you.
But where's the logic in bashing a movie, just because you think the ships to big?
Hell, when you think about all the room you'd need to house a generator that could create enough energy to warp space-time, and have 400 people living on it, have enough room to house, maintain and launch several shuttles capable of housing 7 people each, room for transporters, sensors, sciencelabs, medical facilities, recreational facilities, arboritum and God knows what else for when the plot needed it, the original Enterprise was way to small.