Even in Jane Austen's time there were book reviews. Here are a few thoughts her peers had on her works.
Sense and Sensibility
Sense and Sensibility was criticized the status of women down to the price of tea. In the end people were torn down the middle either by her portrayal of realism or thought she was spot on.
Pride and Prejudice
"the fashionable novel" ~ Anne Isabella Milbanke
"would rather have written Pride and Prejudice, or Tom Jones, than any of the Waverley Novels" ~ George Henry Lewes
"a carefully fenced, highly cultivated garden, with neat borders and
delicate flowers; but ... no open country, no fresh air, no blue hill,
no bonny beck." ~ Charlotte Bronte
Mansfield Park is probably the least popular of Austen's novels (I haven't even read it).
Regency critics praised the novel for its wholesome morality. As for Fanny Price, critics present and past have thought her timid and unlikeable, finding it hard to empathize with her. Jane Austen's own mother found her "insipid". In short, not up to Jane Austen's usual standards compared to her other heroines.
Early reviews of Emma were favorable but agreed that there was a lack of storyline.
Maria Edgeworth, the author of Belinda said:
"There was no story in it, except that Miss Emma found that the man whom she designed for Harriet's lover was an admirer of her own – & he was affronted at being refused by Emma & Harriet wore the willow – and smooth, thin water-gruel is according to Emma's father's opinion a very good thing & it is very difficult to make a cook understand what you mean by smooth, thin water-gruel!!"
Published Posthumously and could be seen as her least polished novels. This may be because it was the first novel she started but abandoned it for Sense and Sensibility. It is best known for it's status as a Gothic parody. Also, in Ian McEwan's novel Atonement, the character Briony Tallis inhabits many characteristics as that of Catherine Morland.
Persuasion was also published posthumously (in fact Persuasion and Northanger Abbey were originally published in one volume) is widely appreciated as a love story and acclaimed for Austen's wit and ironic narrative style. This is also told to be the most autobiographical of all her novels.