I am taking this from the What do contempary Orthodox believe, but though it meirts it's own thread:
It shows how the hereseys have crept in to the churches that adapted or were forced under the Papal Calendar such as modernism, sergeism and ecumenism. And how even traditionalists in communion with these hgeretics have started to take up traits of the heretics.
I think the real reason there are problems in the mainline Orthodox Churches isn't the calendar or the other externals. The externals are only designed to help and guide the internal and it is wrong to get too caught up in the externals (becoming far more legalistic than the pharisees ever were). I feel that all the problems of ecumenism and modernism came to the church via loss of the ascetical life among the laity. I know I don't fast much at all, don't keep vigiliant in prayer etc. But the people that do no matter their jurisdiction tend to overlook the minor issues seperating new and old calendar, the ROCOR and "World Orthodocy" etc, and look to who is truly in Christ. I am very blest to live so close to Saint Anthony's Monastery in AZ because I can see this first hand. Saint John of San Francisco is one of the most beloved saints there...and the ROCOR is not thought to be schismatic. Yes St. Anthony's follows the new calendar, but since they are living orthopraxis to the fullest possible degree it doesn't matter. I think it is sad to see Orthodoxy reduced to a matter of picking the most traditional jurisdiction and getting caught up in the legalistic aspect of it all. Rather than forming the super-true genuine true believer church of whereever wouldn't it make sense to focus more on cultivating Orthodoxy in the heart? Just my two cents on the matter...