Ranked in these QuestionsQuestion Ranking
Pro Light resource usage
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.
Pro Streams to most live streaming video platforms
OBS can stream to any RTMP-enabled service, including Twitch, YouTube, DailyMotion, and Hitbox.
Pro Has over 20 plugins that enhance functionality
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.
Pro Supports Intel's Quick Sync for faster and more power efficient video processing
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.
Pro Several capture types supported
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.
Pro Scene previewing allowed in Studio Mode
OBS allows to look at scenes before streaming them in Studio Mode.
Pro Simple user interface
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.
Pro Stream settings are extremely customizable
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.
Con Can't output to multiple streams at once (planned)
Ability to stream to multiple outputs is planned.
Con Cannot record to multiple audio tracks with Replay Buffer (planned)
It's possible in regular recording though.
Con Captures overlays even when told not to
This software has had a bug for several years where it will capture the Steam overlay and other overlays. This is problematic because your private conversations can be viewed by anyone watching your current or past streams. Privacy issues are a major reason to avoid this software.
Con Does not yet support H.265/HEVC video encoding.
Con Can't link to an audio file as a source
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).