Biggest box office competition for 'The Twilight Saga: Eclipse' is 'The Last Airbender'?

'The Twilight Saga: Eclipse' - Summit Ent.

We've known for some time that Jackson Rathbone's The Last Airbender would be released very near to The Twilight Saga: Eclipse, and months ago, Eclipse was listed right alongside Airbender on Variety's assessment of "formidable competition" for the summer box office.
A lot of Twilight fans have operated under the assumption that those who would see Eclipse this summer would not be deterred by the date of Airbender's release, but Variety has readdressed the situation and suggests that the formidable competition at issue now is between Eclipse and Airbender.

"Eclipse," unspooling June 30, will face tough competition for male eyeballs from Paramount's event pic "The Last Airbender," which opens July 2. Last week, Paramount upped the ante by announcing that it's converting "Airbender" to 3D.

As is obvious in this film franchise (especially with the recently released final trailer), Eclipse filmmakers are trying to reach an expanded audience (namely, more male fans), so the situation of Airbender just behind Eclipse could serve as an obstacle to getting some new bodies in the theaters for the film.
Other than Airbender, it's been suggested that Twelve is a potential box office competitor for Eclipse.
On the other hand, Eclipse does have the advantage of opening first in the week (Wednesday, June 30th), so that might be a factor to consider.