The Brahma Sutra admits two main commentaries, one by Shankara and one other by Ramanuja.
Question: What are the difference between these two commentaries?
Swami Vireswarananda has done 2 translations of the Brhama-Sutras with Sanskrit text, English rendering, and commentary. One is a translation of Sankaracharya's Brahma-Sutra and the other is the Brahma-Sutra Sri-Bhasya of Ramanujacharya. In the Sri-Bhasya translation, he has an Introduction where he explains in detail the agreements and differences between the two, Shankara's Brahma-Sutras and Ramanuja's Brahma-Sutras. It is 50 pages in length so I won't go into a lot of detail. The books are still in print. If you are interested I can tell you where to order from, depending upon what country you're in.
I will quote only the first paragraph of one of the last sections of the Introduction:
From the previous sections we find that all the Vedantic schools more or less agree on certain points, especially in their attacks against non-Vedantic schools. All agree that Brahman, the ultimate reality, is the cause of the world; that a knowledge of It leads to release, which is the summum bonum of life; that Brahman can be known only through the Scriptures and not through mere reasoning or other means of knowledge, the Scriptures being the sole authority with respect to It. But they differ among themselves as to the nature of Brahman, Its causality in respect of the world, the nature of the soul and its relation to Brahman, and the condition of the soul on release.
Hope that helps.