Meh. I like the Sea Creatures and Two Worlds commercials. The rest, well, are a tad over the top. I agree with earlier sentiment that somehow more of United/its product need to be shown/touted in these commercials. A 5-second tagline at the end isn't enough, IMHO.
I also agree these are very creative commercials and very well-done. I'm just not sure how effective they'll be in driving ticket sales.
The "Sea Orchestra" one could have been improved, for example, with an addition to the tagline at the end with something along the lines of "now create in orchestra of your own on United's new International First and Business Class with connections for your iPod. It's time to fly." Then the orchestra would have made sense and could have tied into the product.
But, what do I know...