If you want to make an indoor game then you will not come far with ABT as your scene management of choice.
Though I am not sure how well the latest BSP implementation works with shaders and lots of detailed static meshes applied.

But actually something like a good BSP system or a system with zones and portals is needed then. Torque and C4 have zones and portals. The advantage is: You can manually influence how areas will be occluded. This way you can put tons of details into a zone. Shaders and real-time shadows will be no problem even if your level is huge. Only one room and some geometry visible through a portal in view will be rendered.

Because of this I would also compare the pro edition to these alternatives.