The OB application is great for music but not so great for the ultra low infasonic frequencies found in the Low Frequency Effect (LFE/.1) track of movies, especially action movies. The drivers can bottom out. Also, the difference in room loading of the OB application doesn't produce the chest thump of a sealed or ported sub which is great for music but lacking for home theater.
So if you want the best bass for music only, go with a stereo application of OB subs. If you want the best bass experience for home theater only, go with the sealed or ported application. If you want the best bass for a combination music and home theater system, go with stereo OB subs on the main channels and use one or more sealed or ported subs on the LFE channel(s). Danny has used the combination of OB subs up front and a sealed in the back of the room running out of phase for music only. Which would actually be the ultimate music arrangement.
My Living room system is primarily home theater. With this system I have a Rythmik F12 on the LFE/sub out channel of the AV receiver. My upstairs system is for both music and home theater. In this system I have OB subs on the left and right main channels and a GR/Rythmik sealed sandbox sub on the AVR's LFE channel.
The GR/Rythmik servo subs, whether sealed/ported and OB, are the best I've heard for their respective applications. Choose the configuration that best suits your needs and budget.