DeepSeek V4 vs NotebookLM: Which Is Better in 2026

Last week, I spent three hours trying to synthesize a 140-page technical spec document with a standard chatbot. I kept pasting chunks, losing context, and getting generic summaries that missed the actual engineering constraints. It was a painful reminder that not all AI tools are built for the same job—even in 2026, when we're swimming in capable models.

Two tools I keep reaching for in very different situations are DeepSeek V4 and Google's