Overall an easy and enjoyable watch. I'm a 34 year old woman and have seen some (but not all of) SATC.
I find bits of The Carrie Diaries touching but some of the themes are repeated quite often, and I also find a lot of it very far-fetched.
Carrie's character is a complicated one; on one hand, she's a very wise, sassy, non-fazed, street wise kid who can do no wrong in anyone's eyes and is able to instantly make a deep, emotional connection with anyone she meets (including her seniors).
On the other hand she's a vulnerable, impressionable girl. She has enviable style, looks great in everything and her love of all things 'glamourous' in the city immediately comes through (including a very laid back attitude to the darker side of all this which is generally brushed over).
I personally feel that a less 'perfect' Carrie would work better in this series, as the writers seem to be trying to create an idealistic version of her based on SATC, giving her relationship and emotional wisdom a girl of her age (16) would not have.
Having said that, if you watch it for what it is (a girly, teen sitcom in it's own right) then it's entertaining enough.