Do you learn anything from reviews of your books?

Dear Literary Ladies,
Is there anything to be gained by reading reviews of your books? For most authors, it's hard to ignore reviews; first of all, one is curious, but also, with google alerts and such, everything's in your face 24/7. What was your experience with reviews, and did you learn anything of value from them?

Talk of reviews! I subscribed to a clipping bureau and they come in shoals every day. So far I have received sixty-six of which sixty were kind and flattering beyond my highest expectations; of the remaining six two were a mixture of praise and blame, two were contemptuous and positively harsh. However, the nice ones are so much in the majority that these adverse ones do not worry me much. One criticism was correct—it said the ending of the book was “too poor and commonplace” to match the “freshness and originality” of the first two thirds. One denounced the heroine as “impossible, mawkish and tiresome.” . . .

On the other hand a favorable critic called her “charming” “vivid” “original,” “one of the most delightful characters in juvenile fiction” etc. etc. One thing surprises me in the reviews and one thing disappoints me. I am surprised that they seem to take the book so seriously—as if it were meant for grown-up readers and not merely for girls. The disappointment come in this: —I had hoped to learn something from the reviews. I know the book must have faults which its author could not perceive and I expected the reviews would point them out. But there is no agreement. What one critic praises as the most attractive feature in the book another condemns as its greatest fault—and there I am no wiser than before.

—L.M. Montgomery, from a letter, March 19, 1906