The following article is taken from a 2007 book by Fr. Celier, SSPX, and counters the claim that Bishop Fellay has abandoned the principles of Archbishop Lefebvre by his attitude and position towards Rome and the Holy Father. It's particularly good because Fr. Celier has been a priest for over 25 years, and knew Archbishop Lefebvre personally.
Please see the SSPX archives for more... http://sspx.org/en/articles-index