I spent some time to compare Wordweb http://www.portablefreeware.com/index.php?id=1467
vs. TheSage http://www.portablefreeware.com/index.php?id=782
- Easy to use, simple interface nobody's going to get confused by. Reminds me a bit more of an actual dictionary.
- Random word view.
- Has ctrl+alt+w to look up words or selecting and right-clicking while holding control. Very easy to remember.
- Weird license, asking me how many flights the user has taken. I understand and definitely support the point behind this, but its still odd.
- Strange color-coded tree view took some getting used to, but is quite powerful.
- Love the tabs, anagrams, and quick look at Synonyms, Antonyms Hypernym (I had to look that up ... it's a word that's more generic than the given word), and Derived words. Awesome.
They both are similar in concept, but very different execution. As far as I was able to tell, one isn't better than the other.