I was on Bit Torrent about two and a half years ago and the first client I used was the official one. The official client turned out to be a great disappointment. The allocation of disk space is not good and it takes me a long time to kick off before I really get anything on my disk. I have tried several bit torrent clients with the python core, including ABC and burst, which are all based on shadow experiment core. They took a huge amount of resources, though and my super old computer would simply hang with more than sixty connections. Their allocation of memory is not satisfactory either. Then I though, it the inefficient language, python, must be the culprit here. Then I turned to clients whose core are written in other language. There are a few alternatives, Aruzeus, a very famous one is based on Java, BitComet is based on C plus plus and libtorrent also comes with a default client in C plus plus. BitComet pleased me. You can connect to virtually any number of peers you would like to and the core is not so hungry with CPU resources. The bad thing about it is of course that it is not open source, and God knows what the author has put into this piece of software. However, it is the only client that you can use to connect more than 500 peers with download rate of more than 1500KB per second. I run this piece of software on a very old Pentium 2 400MHz machine and there is no lagging or hanging even at this load. So it remains unrivaled as my favorite bit torrent client.
For exeem, the new coming p2p software, I think it is not very stable at the moment. Some users also complained that some nodes cannot be connected. Wikpedia has come up with the following criticisms.
Quote
Criticisms of eXeem arose soon after it debuted (and after sloncek's 'unveiling'). These include:
eXeem's for-profit operating model, including support through advertising (much akin to Kazaa) and a public beta that included the adware program Cydoor. A spyware-free version, eXeem Lite was subsequently released, and eXeem has since dropped Cydoor from version 0.21 onward.
Closed source code development, in contrast with the open source model followed by the BitTorrent specification, which eXeem aspires to replace.
No initial Linux or Mac versions, with no ability of third parties to port the code beyond Windows (as eXeem is closed source).
Point 3 is not fair but I think points 1 and 2 are quite justified and valid.