I've been using Phex now for a while on my ubuntu partition, and for the most part I like it, although here are some things that might need to be fixed/improved (mostly related to magnets):

• Magnets with urn:bitprint:<sha1>.<tth>&etc... should be supported (even if you just ignore the tth, just parse out everything between 'bitprint:' and '.' and treat it as it were urn:sha1: ). bitprint is pretty common, so supporting that is important to me.
• support for multiple urn: types. Currently Phex requires you to put urn:sha1: as the last urn: in the magnet, so if you have another one (like urn:ed2khash: after your urn:sha1: ), phex won't find a sha1 for your magnet download.
• I had started a download for a certain file with a magnet, but Phex couldn't find any sources. When I searched for the file manually, any sources that were found, didn't get added to the download (even though the sha1's were identical, only the filename was different). When I doubleclicked the sources, Phex started a new download instead of adding the sources to the existing one.
• Sometimes the interface hangs (especially when changing options), and I have to kill the java process and restart Phex. I also have redraw problems. I also noticed that Phex somehow had set my upload speed to 0KB/s, which made uploading impossible. It seemed to hang every time I tried to set the slider higher. Maybe this last one is more related to my java settings, or Xorg, but I just want to know if you guys know about it.

For the rest, i found Phex to have the right mix of ease of use and advanced settings to fit my taste. I'm just trying to help make this app better by giving you bug reports/suggestions .