More puzzles. Plus, I find them harder (if you think that's a good thing). I was able to do the Lite version in under an hour, without needing to ask people for clues. However, there a good number of puzzles in the paid version that I've really needing to seek out help from others (like here).
Otherwise, the apps are identical in how they work, look, etc.
I think it's well worth the 99 cents. Be aware that the 99 cent version has ads on the web search screens. The developer says that there is a "pro" (i.e., more expensive) version that doesn't include these ads, but I've yet to see it. The ads are not a big deal, in my mind.