Well, that's a bit hard to answer! Pro will let you connect to more ultrapeers, potentially give you better search results & let you download from more hosts.

But, at the same time, improvements have been made in the newer basic versions. Have a look at the changelog here to see what's been done recently
http://www.limewire.com/english/cont..._history.shtml

Keep the installers for both versions, that way you can change back if you're not happy with whichever version you decide to run.

Hope I haven't confused you too much