OBS Studio and Streamlabs Desktop are built on the same underlying engine, but they serve different creators. OBS gives you direct access to every encoder setting, filter, and source property — it's a professional broadcast tool that requires learning. Streamlabs wraps the same engine in a creator-focused interface: integrated Twitch/YouTube alert boxes, a curated overlay library, and a built-in merch store.
The performance difference is real: OBS typically uses 10-15% less RAM than Streamlabs for equivalent scenes, which matters for gaming PCs already running demanding titles. Streamlabs Ultra's multistreaming to unlimited destinations simultaneously — one of the most requested features in streaming — justifies the $149/year for creators building audiences on multiple platforms. For pure streaming performance on a constrained machine, OBS wins. For creator experience and features, Streamlabs Ultra wins.