Thank you, gentlemen

Looks like there is much more exalliens or first generations here than I would have imagined.
It was not difficult, we live in States for almost 13 years and I am married to an American for 15, there was very little for me to study to pass the test. Like names of my local representatives and some details from US history and civics - like who worked on Federalist papers.
It did not take too long, I actually applied in October 08. The filling fee is about $700 and it includes fee for biometric data (fingerprints). I have now at least 3 sets of fingerprints with various offices. I would think the Fairfax office is one of the fastest in the country because of D.C. but I can only compare to what I heard of people waiting 10 month for an interview. I passed the test on Tuesday afternoon and they offered me oath ceremony the next morning at 9. The lady said, that if I had the interview before noon, they would let me do the oath the very same day.
The ceremony of the oath was nice and friendly, they didn't mind picture taking etc. We took kids to see it as a civic lesson

and the crowd was very colorful.
Downsides:
- Can't scare the kids anymore in the Men in Black style: I am an alien

- My wife is no longer sleeping with a mysterious foreigner, she got an American with thick accent instead

- And of course, as Bird pointed out, I can't say anymore things like "we don't do it in my country" or "you Americans, yadda, yadda"
Don't get me wrong, it was the right thing to do!