Manus did a lot of harness work to make up for gaps in Opus 4.5 tier models. I tried it for a time - they had a great deep research/PDF generation pipeline, parallelization, etc. The bitter lesson has now come for them: the latest models no longer have these gaps and the entire premise of having a unique product focus on this area is no longer relevant. Even Ant/OAI have let their "Deep Research" capabilities fall by the wayside, you can largely get the same result by asking for subagents or simply "keep going" style prompting.