This product is fantastic if you're on the go with your beloved books and for obvious reasons of space, weight, and convenience. I try to always carry it with me as I usually like to look up those obscure difficult words as well as some literary words used in some of the books I read. I can say without any doubts that this is my faithful companion.
I have even used it when teaching my ESOL students without the hasle of checking on a book dict. when I can't find specific words or I just simply have temporary amnesia. Using the helpful thesaurus I can enter a synonym of the word I'm looking for and in return the machine renders several options from which the word I was seeking appears.
It's a very comprehensive dictionary as its content spans from archaic to slang words. It also has an idioms dictionary (covering phrasal verbs too) and some games and other functions which I don't really use but that could be appealing to some.
I recommend it to any native speakers, readers, writers, and teachers alike, as well as learners of English who are genuinely engaged in their studies (Aimed for: Higher level Upper Ints, Advanced and definitely proficiency students).