I was struck by something this morning while meditating on Charlotte and Lizzy's choices regarding Mr. Collins. In Ch. 20, we have this speech from Mr. Bennet: An unhappy alternative is before you, Elizabeth. From this day you must be a stranger to one of your parents. Your mother will never see you again if you do not marry Mr. Collins, and I will never see you again if you do. It seems to me that in this passaage, JA is saying the choice is between sense, represented by Mr. Bennet, and economic security, represented by his Mrs. If Lizzy marries Mr. Collins, sense will be a stranger to her. If she doesn't, she risks her future economic security.

I believe this explains, in part, Lizzy's harsh reaction to Charlotte's engagement. She thinks Charlotte has sacrificed every better feeling to worldly advantage. She has chosen to be mercenary, rather than sensible. This goes along with Mr. Bennet's later thoughts: it gratified him, he said, to discover that Charlotte Lucas, whom he had been used to think tolerably sensible, was as foolish as his wife, and more foolish than his daughter!

Charlotte tries to defend her decision to Lizzy in this way: I am not romantic, you know; I never was. I ask only a comfortable home; and considering Mr. Collins's character, connexions, and situation in life, I am convinced that my chance of happiness with him is as fair as most people can boast on entering the marriage state. I think she is saying her choice is between romanticism and prudence--between being like Marianne Dashwood of S&S and being like Elinor. I think she is implying that Lizzy is taking a romantic (in the negative sense) view of things. Charlotte implies she, on the other hand, is using her head.

But the earlier exchange with Mr. and Mrs. Bennet, IMO, belies this approach. This is not S&S. Lizzy does not choose romanticism over sense. In JA's view, Lizzy is the sensible one. It is not sensible to knowingly marry a man like Mr. Collins. Any woman who does so, gives up all claims to sense.

There has been a lot of defense of Charlotte by other Pemberleans based on her lack of prospects, etc. Of course, each of us is free to decide whether we agree with Charlotte. But I have yet to see anything in the text that indicates Austen believes Charlotte made the right choice. I believe this "unhappy alternative" passage gives us the evidence that the author agreed with Lizzy, not her friend.