Actually, BAC can be used with any scope; it is just easier to do with illuminated reticles. the trijicon scopes marked "BAC" have reticles that are always illuminated.
The TA11 also has: longer eye relief, larger exit pupil, 1/4" clicks, different reticle options
However, if you find the size and weight problematic, the TA31 offers both BAC and the different reticle options in the same size package as the TA01.