Perhaps if Kerplunk bothered to read the question title, as well as the question itself, everything would make sense to him or her?
Limewire is the most popular P2P client. Since it uses the Gnutella network by default, this means that the widest choice of available files is likely to be found by using Limewire or any other client (such as BearShare) which uses the same network.
eMule uses the eDonkey network by default. There are fewer people using clients on this network so the total number of available files will be smaller than with Limewire or Bearshare. However, eDonkey offers some advanced techical features which means that some people will experience faster downloads. (This applies particularly to P2P users who are signed-up with ISPs that use bandwidth throttling on default P2P ports).
Both Limewire and eDonkey are configured to offer a greater number of downloads to users who make a large number of files available for uploading but they probably have different 'quota' settings. (i.e. someone who makes only a small number of files available for uploading might find one client better, while someone who offers many thousands of files might the other client better for their needs).
Different users will have different experiences with these two programs, depending upon how many files they make available for upload and whether their ISP uses bandwidth throttling. The only way to find out which one suits your needs best is to try them both.
Chris