Sealed cabinet subwoofers will have a higher F3 than a ported one with the same driver. A sealed cabinet rolls off at 12db/octave while a ported one rolls off at 24db/octave. This means that while a ported cabinet may have a lower F3 than a sealed one, the sealed box might actually have a response that gets lower than the ported one, because of the less steep rolloff curve.

A sealed box will usually require more power to drive it than a vented box, indeed look at the power rating of the ECS10 vs Outlaw's other (vented) subwoofers.

A sealed box is less sensitive to the Theile-Small parameters of the driver, so it's easier to design. A ported box alignment is limited in freedom, while a sealed box can be tuned to specific Q's. BTW anybody know what the QT of the ECS10 box is?

The THX specification calls for a QT of .71 (Butterworth) which gives the lowest F3 without any overshoot (booming).
(Hate to say it but the Outlaw bookshelf speaker and the Outlaw MTM speaker can't meet THX specifications because they are vented boxes. By design THX certified main speakers need to be sealed boxes with a QT of .71 and an F3 of 80hz to match the subwoofer crossover frequency.)