Longman the best

I have at least 5 dictionaries from Longman and all of them are well organized, easy to use, sync with the cloud, The sounds let you practice and have a better idea of the pronunciation, better than having the hardcopy only. Try phrasal verbs and the activator thesaurus those are great too.

Leonardo Galvez about Longman Advanced American Dictionary (with audio), v6.0.4