Most advanced privacy coin today would be XSPEC as far as i know it has the OBFS4 feature which facilitates undetected use in countries that block Tor,such as China & Iran.It has ring signatures for complete transactional anonymity,making it impossible to determine the true source of funds for a transaction,and would have implement the stealth address feature which makes this coin the best,research mate so you could easily find which coin would have a great future.