gav223,
If your going to get the Pro version. Make sure you get it from the official site:
http://www.limewire.com/english/content/download.shtml. Any place else should be considered a scam.
You will not see much difference between LW Basic and Pro. The Pro version connects to more hosts and downloads from more sources, so the potential for better search results and faster d/ls is there. If your looking for a dramatic difference, you probably won't find it. A lot of us consider buying Pro as a donation to help fund future updates and to keep the program going.
As for whats the best program, you'll find as many opinions as there are programs available. I'm partial to LW myself. I also use
Shareaza sometimes, but LW is faster
.
Don't download any P2P programs that aren't free or don't offer a free version. There are a lot of scam sites out there looking for a quick buck
.