I am relieved that nostalgia is not the motivator. Nevertheless I do recommend you read Fr Andrew's essay on Converts and converting. It may answer better than I your question.
In your second post your ask what my opinion is of the 'Old Believers' and 'Old Calendarists'. My opinion as an individual has little importance but rather the 'mind' of the Church does. First, may I reverse the order?
There is in the Orthodox Church a Church calendar, and an innovation going back to 1920, the Revised Julian calendar plus in Finland simply the Julian calendar. The Church of Greece introduced the innovation of the Revised Julian calendar in 1924. The sad story of this rendering of liturgical unity within the Orthodox community is complex, and unedifying. You can find more on this and the fruits of the 'calendar question' elsewhere. My sense of it is there are those who adhere to the Church calendar and there are those who do not, i.e. there are no Old Calendarists. Sadly, on either side some and only some who taken up entrenched positions. Others preen themselves with the knowledge that they are 'canonical' but appear only to use those same canons metaphorically to lay into traditionalists, in their ecumenism and other activities the canons seem forgotten. Others see themselves and only them as a last faithful remnant. Between are those who may differ on the 'calendar question' but struggle to follow Him.
The 'Old Believer' schism is one of the saddest parts of the history of the Russian Church - a Church which has produced more martyrs than any other in history. The easy answer would be to say the Old Believers were right to treasure their Old mode of veneration, but erred in not following their bishops and adjusting to the 'reforms' of Patriarch Nikon. I have met some believers who follow the Old Rite, but within the Russian Church, having been received back. The Russian Church has consecrated a bishop for this community and both he and his congregation appear truly to follow a life of Christian ascetic struggle.
In one sense I see looking back through this response to your post I have perhaps not answered. And maybe others might answer far better than I. In trying I am reminded of a discussion once with a very learned but modest priest-monk. I volunteered my wish to visit some placed of pilgrimage or associated with great Saints. The priest-monk was very quiet for a time and then, dryly, asked, "Why?" My answers were the usual. But he quietly said, "You have everything here, a bishop and his congregation. There is nowhere more holy, more catholic, but your struggle is here within you".
In a sense if he was here I feel he might say, these are not the questions.