What are some alternatives?
When comparing Orbit Downloader and Transmission, you can also consider the following products
DownThemAll - DownThemAll is a free extension for Firefox that is designed to allow you to download multiple links or files on a page without having to click each link.
qBittorrent - Lightweight and open source torrent client that runs on all major platforms.
JDownloader - JDownloader is a free downloading tool that enables you to download files from over a hundred hosting sites. The tool is compatible with Linux, Mac and Windows operating systems. Read more about JDownloader.
Deluge - Deluge is a full-featured BitTorrent client for Linux, Unix and Windows.
Free Download Manager - It is a powerful modern download accelerator and organizer for Windows and Mac.
Vuze - Vuze is a free BitTorrent client used to transfer files via the BitTorrent protocol.