I agree that Monica's personal life is only good in small doses, but at the beginning of this season, when Clyde was working for her and they were showing her in the office, she was awesome. I like the show when it focuses on the work stuff more anyway, and she is such a ferocious B in that setting that it is a lot of fun to watch. As an aside, I have been around women like her in the finance world, which may be why I like the character so much.
When this show first went on the air, I didn't think they would be able to pull it off because the subject matter was too esoteric for 95% of the viewers, but the writers have done a great job keeping it smart while making it understandable. They use a lot of jargon that I don't know, and I know the consulting industry relatively well, so I imagine that it can be hard to follow at times for a lot of viewers.
The clients are hilarious, and I am sure that the writers based those clients on real experiences of consultants that the writers met in their research. The main firm is based on Booz Allen, and Monica's firm is McKinsey (I think they call it "Kinsley" in the show).