There's protocol optimisations that came from being... well a later protocol.
ed2k chunk sizes are too big, and queue sizes are huge which is the opposite paradigm to torrent.
However, i think torrents main problem is huge. Trackers, nazi admins, trading, lack of sharing, etc. Its inbred into the whole design and I just don't think the security or the technical advantage of the protocol is there to justify an 'upgrade' for myself.
Here's the biggy to get you started in emule... once you've set everything up, you've got ports open, you've set up a decent upload / download settings for yourself; you need to 'bootstrap' yourself into the network... that is, you need to click a whole bunch of movies, music, games or whatever your after, and then leave emule alone for a couple of weeks.
The idea is you make yourself known to like minded peers (movie taste similarities, etc.) that will have you recorded as uploading to them. This gives you credits, credits give you a queue boost, queue boosts mean you get your 9.28mb chunk slot quicker, which means you download quicker.
So I personally queue up a long list of ed2k links and don't bother looking at my client very often. Infact, I run emule on a server and use an application called "ed2k linker" which send the ed2k link clicks from one of my pcs to my server.
Downloads fine.
For a demonstration of speed potentials, queue up a season of the simspons or something similar