This matches my experience. The Culture is fascinating to read about independent of the books. Here's a short essay by Ian M Banks (the author of the Culture series) about the Culture:
While I totally understand the intent of introducing the Culture from on outside point of view.
I think "Consider Phlebas" was not as enjoyable as some of the other books.
I thought Vernor Vinge's A Deepness in the Sky presented a much more sympathetic picture of a cosmopolitan trading culture, in its clash (and hybridization) with a conservative warrior culture. That book did make "the liberal capitalists" sympathetic.
