DeepSeek V4 vs GPT-5.5 vs Qwen3.6: Which Model Should You Use?

This post evaluates and compares three large language models (DeepSeek V4, GPT-5.5, and Qwen3.6-35B-A3B) based on practical tests relevant to AI application development, including live information retrieval, concurrency bug debugging, and long-context analysis. It demonstrates how to connect DeepSeek V4 to Milvus for retrieval-augmented generation (RAG) pipelines, providing a concrete example of integrating external knowledge bases with LLMs. The analysis covers model specifications, performance in specific tasks, and considerations for deployment and cost.