The good bits - excellent keyboard (compared to some others); good screen (although highlighting can make it difficult to read sometimes); fast (if it can find an answer, but see below).
Bad points - if it can't find an answer (crossword solver) it doesn't always tell you, it just keeps looking until you clear it; only 13 letter anagrams allowed (up to 15 sometimes required for the Telegraph crossword!); insufficient synonyms presented (a previous Oxford Thesaurus based solver was much better); unnecessary redirection through Dictionary is required to get to Thesaurus.
Overall, though, it is good value.