ED2K is essentially the same thing as eMule. ED2K = eDonkey 2000. They both use the same links.
I've used eMule for the last couple years and have NEVER gotten a virus by using it, just LOTS of free stuff. Just make sure you choose stuff through trusted links and not just using the search function. One thing that is nice about eMule is that it uses almost no resources for it to run. I've ran CPU intensive games with it running in the background without a hiccup.
The biggest problem with eMule is that it can be very slow. It can take 2-5 days to get a 3gig file, or it could slurp up the file in just an hour or two......it depends on the amount of sharers and your bandwidth.
I've got huge boxes of PC games, loads of music discographies and hundreds of utility programs for PC through eMule.
I've never been hassled by my ISP for using it......but it's my understanding that I have one of the cooler ISP's that refuse to give names to groups like the RIAA.
Tips for eMule:
Don't leave stuff you've downloaded in the shared folder. Use only servers that provide "obfuscation", which means they attempt to confuse anyone trying to see what you're downloading. You can use programs like peer-guardian to prevent known RIAA-like bastards from seeing what you're doing, but I've never bothered with that. Use only websites that provide links, don't cold-search for stuff. Be VERY patient. Files can take awhile to even start moving. If you have a router, set the appropriate UDP and TCP ports and disable them when you aren't using eMule.