I guess that depends on whether you want to be free to live as a Christian, or prefer to have aggressive secularism in its multiculturalist incarnation rammed down your throat, and whether you want your country to have its own economic policy or to have its economic decisions dictated from Brussels (and indirectly Berlin).
Full disclosure: my tag-line is a quote from remarks Slobodan Milosevic made when the kangaroo court in the Hague refused to allow him to show photographs of Bosniak jihadis exulting over piles heads from decapitated Serb prisoners. If FR gave us more room it would read
"And when they behead your own people in the wars which are to come, then you will know what this was about." -- Slobodan Milosevic
As compared to Putin who annexes neighboring countries, demolishes Catholic and Protestant churches and allows Chechnya to impose elements sharia law, including banning gambling and alcohol and requiring women to wear headscarfs? Serbia has the option of not joining the EU.