Its just small things like for example:

Being able to right click in the library tree and click "Share files" and be able to find the folder that you want to share quickly. With Limewire i have to go Tools>Options>Share files>add. The Shareaza way just seems more convenient.
Also sometimes i find the need to quickly find a file in my Library, Shareaza has a little find files input box at the bottom right where u can easily search and retrieve the file you are looking for. Which is quick and effective.
Another thing i dont like with the LimeWire library is that when you click on a main folder, for example called "mp3's" it doesnt show all of the files in that folder if there are lots of subfolders containing music files, such as the artists or an album. I have to manually click on each of the sub folders inside "Mp3's" to view the list of mp3's i have.

All these things sound kinda small and trivial but are very convenient and efficient.