KTorrent is an official BitTorrent client from KDE.
ktorrent is available in universe repositories, so you can use it with any flavor of Ubuntu, even though it is generally packaged with the KDE desktop environment.
Whether or not any software is good is a matter of opinion, but KTorrent is a full featured BitTorrent client. Since you are already familiar with the user interface of KTorrent, you will not have to learn how to use another client.
KTorrent is open source software and it is developed by the KDE Community and is bound by the KDE Software Privacy Policy, which has the General Principle:
As a general rule, software produced by the KDE Community does not
collect, transmit or otherwise transfer information from end-users
devices except as a result of an explicit user action.
This privacy policy can be especially important with BitTorrent clients because there are so many BitTorrent clients out there that are laden with advertisements or malicious software. Thankfully, that is rarely the case with open source software, especially software in official repositories where the code is reviewed by the community.
Because it is designed alongside other KDE applications, installation may automatically install several other packages--dependencies that you might not need to install with another BitTorrent client.
You can use the GUI package manager to find and install KTorrent, or you can use the following in a terminal:
sudo apt update
sudo apt install ktorrent
