Besonders hilfreich. Ich danke dir. Martin aus London

Unglücklicherweise is the same as unfortunately. Leider is like sadly. I'm pretty sure it has the same root as the adjective 'leid' in 'Es tut mir leid' ('I'm sorry'), so In my opinion, 'Unglücklicherweise' is more objective, while 'Leider' is more subjective. But the use of these words really depends on the sentence & the meaning. Both can seem harsh depending on what you talk about and who you are talking to..