Since the upgrade to OS10.2.6, many users are reporting that Limewire will quit whenever the machine sleeps and regardless of the setting in the System Preferences.

And, that is not the answer to the question posed in the original posting. The resume button was disconnected many upgrades ago. The developers took the decision to help reduce a general traffic management problem on Gnutella. Thus, you have to manage the downloads which are likely to stall quite frequently regardless of the size of the file being downloaded. The standard approach is to retain the original hit in the search box for each download. Whenever a download fails, highlight the line in the downloads box and kill the download. Then restart the download from th eoriginal hit in the search box. Only if that fails do you need to go on to the research strategy.

And you are correct that life can be easier for p2p applications in PCs (there are, after all, rather more PCs in the world and so more effort is invested in perfecting p2p applications). However, the brief advantage in efficiency for this purpose is rapidly lost when you compare the overall inferiority of PCs to Macs on general performance criteria. So, yes, buy a cheap second-hand PC for p2p but keep the Mac.