It is an ease for me
I use N26 since the first time I arrived in Germany.  It has been more than two years.  I never have issue with security while I do online transactions.  
It is very simple to use yet it covers all possible online banking acitivity that I need.
I have two experiences of contacting customer support.  For me they are really friendly and helpful.
I would recommend N26 to anybody.
As a foreign student, I have no problem with the legal status of this bank.