Just to give at attempt at answering my own question I did some research and came up with this.
Transmission is the default BitTorrent client of Ubuntu and does favourably. Customer reviews in the software centre give it a 4/5 rating with those less than satisfied with it citing the following as limitations/problems:
- "Very basic..."
~ Michael Alderson
- "Works fine and pretty much stable, but lacks some even the most basic features. Also, the interface seems a bit cumbersome."
~ E S
It was unanimous among those that did a review of Transmission in the software centre that it was a relatively stable alternative over other BitTorrent clients.
As of the time of this answer (14 Dec 2012) the software centre is lagging a little in the version of Transmission it provides. The latest version in the software centre is 2.61 whereas the latest version of it to date is 2.73.
qBittorrent rather unanimously receives positive reviews from users with the review of BitTorrent clients http://www.techsupportalert.com/best-free-bittorrent-client.htm [mainly aimed at those wanting a free client for Windows] quoting its stability, low RAM usage and consistent CPU usage and encompassment of basic features as its strong suits and its inability to serve multiuser operations being its main limitation.
In the software centre the sole limitation of instability was quoted as an issue with the client receiving an approximate, overall star rating of ~9/10. (4 & 1/2 out of 5)
Likewise as of 14 December 2012 qBitTorrent is lagging behind in the software centre a little. The latest version in the software centre being 3.0.5 whereas the latest version to date is 3.0.6.
Vuze is a popular BitTorrent client not only in Ubuntu but also in Windows. In the software centre the primary complaint about it is that it is, 'buggy,' or, mostly, in other words it is prone to crashing. One reviewer even stated it is the buggiest app in the software centre they had seen in their six years of using Ubuntu.
Other than that the major complaint is that the software centre is lagging heavily when it comes to the latest version Vuze it provides. (4.3 vs. 4.8 being the latest release)
This problem, may, however, be overcome by downloading the tarball found at http://www.vuze.com/download.php extracting it and then running the executable shell script, 'vuze' in the extracted directory.
Overall in the software centre it receives 4/5 stars with most quoting its benefits as being its many features and ease of implementing it.
As far as reviews go there are none in the software centre the pros and cons given at the review earlier quoted (http://www.techsupportalert.com/best-free-bittorrent-client.htm) are:
Pros: Cross platform client that is stable for the most part and efficient. Well accepted at private trackers. Excellent performance on torrents. Good help resources. Clean install, no addons etc.
Cons: Issue with Add Torrent screen not showing files for magnet links so they can not be deselected before adding to download (they may be deselected after adding).
With the reviewer also stating that its performance, in his/her opinion, was a little behind that of qBittorrent.
The review, http://www.techsupportalert.com/best-free-bittorrent-client.htm, says that the pros and cons of this software are: (although the software centre does not store it so no reviews from that source are available)
Pros: Generally stable and efficient with a good variety of options. Developers are active and responsive to user requests. Attractive interface. Good help resources. No addons etc. during install.
Cons: Help resource, though very good, could use some more. Smaller operation, which you may or may not like. Performance on test torrents was not up to the Superior clients.
Finally, if you plan to be torrenting media files, Miro may be the client for you. It has the capability to run a wide range of media files and remembers where you, the user, were up to in watching/listening to your media files. In the software centre Miro received a 3/5 star rating with dissatisfied reviewers citing bugs and advertisements as the reason for their dissatisfaction.