gnutella is a network for users, not a site. If you think that by using LimeWire you are going to a site, you may have been scammed by site that sucker the innocent.
OTOH, unusually fast downloads are probably misleadingly named files (check their sizes to be sure). If you are getting too many corrupt files that you know should be good, then your downloads.dat and .bak files may have become corrupted (quit, delete the incomplete folder--this loses all the old incompletes--and a new, uncorrupt one will be created next time you open LW).
As for Pro--get it to support gnutella development, not for any 'tricks'. Scam sites ask for money before you try--LW doesn't.
If you want 'alternative sites' try here
http://www.gnutellaforums.com/showth...threadid=24819