Have had no problems at all with Limewire.
There are some bogus files and nasty spyware stuff there, but use your head and you won't go wrong.

For example, the guy I was talking with on the train who downloaded a malware file thinking that it was an episode of "Family Guy"..... the fact that the file size was only 380kb should have tipped him off!!

I don't know anything of this P2P stuff, other than I use Bit Torrent to get official Linux software versions. This thread tweaked my interest, so in the name of research I tried to get a random film (French Connection). OK, I know its breaking copyright law, but I wanted to test out the concept. I tried Bit Torrent and downloaded Limewire, searched on Mininova etc. for seeds, and pretty much gave up after a couple of days. I could have waited till lunchtime tomorrow, and gone down to the library, picked up a free DVD loan, and still beaten P2P.
The best download speed I could find was less than 25K on a 2M connection- about a 1.5 day download! Am I missing something, or is this typical? I was also less than impressed with the seedy smut and mal-ware 'push the fart button' type environment it's necessary to enter. Not for me!

Yup, that's the problem with P2P and why I'd only use it as a last resort after Newsgroups and Torrents.

With P2P as the name suggest (peer to peer) your download speed is limited by the others upload speed so is never likely to be very fast. With torrents you are taking advantage of the upload speed of several(sometimes hundreds) of other users at the same time. With Newsgroups you are using their dedicated servers which have high upload speeds by default.

I found that if Limewire is downloaded from the official, or at least a reputable site (say, Download.com) there is no seedy "push the fart button" type web environment.Nor pop-ups, nor rude pics.Nada.
Seediness may exist - and often seems to - when doing a video search; rarely with an audio search.
As ChocksAway points out, download speed is limited by other users upload speed, but also by the configuration of the program (good forum info available for this) and the number of online users hosting the particular file.
Worst download speed IO've had <1kb. (1 host, modem, across the universe.) Best, 117kb (multiple users, t3).
I would have to be mighty desperate or masochistically curious about my AV's capability to download any .exe or .rar etc file using this. Heard about quite a few nasties. Spyware, viruses, etc.

Edit Just searched for French Connection, out of curiosity. Within 1min the film was located. (117Mb,avi.) It was no. 15 of the available titles; the other 14 were all porn.

Limewire is great for music and videa, E-Mule is great for everything else.

About this newsgroup thing - are there any free ones out there that actually work?