Minutemen has been great, I can't fault it. I've not been reading the other comics so I can't comment on those.
I am pretty annoyed (although not overly shocked) that the Black Freighter/pirate story is in all of the comics so you can't actually read it all without getting all of the comics. This makes me sad :'(
I started reading it and it was okay but then it got worse at the Comedian issue so I stopped subscribing and I think the whole series is an injustice to Alan Moore and should never had been made unless Alan Moore was going to write it with Dave Gibbons drawing.
If you read it as a stand alone mini-series without comparing it to the original, you will find reading Before Watchmen quite enjoyable, a truly one of a kind experience. The art is superb, the story line is amazing, the dialogues are incredible, and whole atmosphere of each issue is truly wonderful.