Open Broadcaster uses relatively fewer resources than competitors, especially when streaming using Game Mode and by limiting the number of frames per second to 60 or lower.
Open Broadcaster has a clean and simple interface that is easy to understand even for people who have never used a streaming application before. It has a "Start Streaming" button on the bottom, which, when clicked lets you stream from your chosen source.
Open Broadcaster lets you add different streaming profiles, each with its own settings. Each profile can have its keyboard shortcut to start or stop recording, custom resolution, frames per second or even the audio codec of choice.
There are multiple capture types that can be used to stream. By clicking in "Sources Window", you can add the type that you need. Windows Capture, for example, as the name suggests, captures the windows. Monitor Capture is similar but captures the window regardless of where it was, this way you can for example capture the whole monitor or a sub-region of the screen. But the most important capture type by far is Game capture, which allows users to record full screen captures of games.
OBS has over 20 plugins to choose from, including one's that allow adding video files and any other media supported by VLC as a source, integrating Twich chat and switching scene depending on what window is in focus.
Quick Sync is hardware video encoding and decoding technology that's comparable in speed, compression ratio and quality to x264. Since Quick Sync is a dedicated hardware core on the processor die, it allows for faster and more power efficient video processing.
You can download a plugin called DirectShow Audio Source, but you're only given options to use audio inputs (mic, speakers, etc...). You cannot simply select a wav or mp3 file to loop (going AFK or BRB for example).
XSplit offers a free version that includes both XSplit Broadcaster and XSplit Gamecaster, but is limited to .aac 96 kbps mono audio, .mp4/.flv@30fps video and advanced features like image overlays, Twitch integration or a preview editor.
Wirecas has support for rare advanced functionality such as IP cameras, remote desktop capture, 3d virtual sets, image slideshow, scoreboards, projectors.