Deepseek has been great for my academic research. I used it recently for a large scale RAG task with 10-Ks going back to 1995. I tried different models from various providers to get a sense of accuracy-cost tradeoff. GPT 5 mini was the best but still costing close to an estimated $10k which is way beyond my research budget or what my department would pay. Then Deepseek V4 Pro released and I tried it when they announced the pricing. The results were way better than GPT 5 mini and the cost was unbelievably low. I went for it rushing to finish the job before their promo period ended (which they made permanent anyway). It cost me only $450! That’s insane savings compared to GPT 5 mini.
I wasn’t concerned about data privacy as 10-Ks are public and quite likely part of the model training.