I picked this up after reading a critical analysis of three series: Gossip Girl, The A List, and The Insiders (Glenn, 2008. Journal of Adolescent and Adult Literacy, 52:1). I hadn't heard of these series or the Gossip Girl television series.
Glenn doesn't look very favorably on these three series. They all take a look at the lives of the rich and privileged. I have a somewhat different take, at least on the first of the Gossip Girl books. I didn't read this as an endorsement of the privileged life style. I certainly didn't want to become one of the main characters. They seemed vulnerable to exactly the same pressures, anxieties, and social trap of any teen.
The book did portray more sex, drugs, and alcohol than I would expect of a YA novel. However, I didn't find the portrayal one that would attract me to those pursuits. Instead, for the most part the "bad" behaviors appeared to be just that--self destructive and unattractive.
Generally I didn't find the writing compelling. It is readable, but I am not going to run out and read the next title.