I honestly wasn't that impressed by Lightning and uninstalled it after a few days.
First, it has a small section toward the bottom of the UI which flashes occasional ads or graphical tips, unfortunately that just acts as a distraction and I didn't find a way to turn it off.
Second, I use Vista and have begun to utilize its search capabilities in the same way that I use OSX + Spotlight at home. While I cannot say that I believe Vista's is better, it certainly comes close enough to Spotlight for now. However, Lightning's entries are not available via the OS search mechanism. I made several entries, waited through the day then tried to look them up to no avail.
I should add a disclaimer that I use a tool called Yojimbo on OSX to act as a reference repository and really do like it. So I do compare my tools to it.
Regards,
Kelly
