BTC has capability to create new account on offline computer and send coins to it without ever going online.
That way I can keep large chunk of my coins on my offline computer without worrying about keyloggers. Even if they got there during installation they won't be able to send anything because it's offline.
Such possibility doesn't exist in NXT.
Unlike BTC, new NXT account has to send to internet at least one outgoing transaction to become fully initialized by the network, and just sending money to that account is not sufficient for initialization. Otherwise collisions may spoil it.
Do you know if Ardor will fix this drawback?