No, I have not tested other coding agents. DeepSeek works well enough for what I need. From what I've seen I can guess that Claude, now with the new Design feature, is ten times more effective as it also creates images, styles and media, thing that DeepSeek doesn't, yet, but for now I try to keep my designs simple and find a free hero pic somewhere to keep the costs low and the mental friction lower.
So yes, there might be better coding agents but for the price and the results I am pretty satisfied.
My workflow is simple as a solo developer, for simple tasks I write a single message in the terminal and watch it do its magic, for complex tasks or the starting of a project, I write a start.txt prompt with detailed info about the app, the tech stack, the auth protocol, database design, rules and conditions, business intelligence, styles dark/ligh and responsive, and then watch it run for over five to ten minutes developing a whole fully functional app from zero. It doesn't hit 100% of the requirements most of the time (close to 95%) so I do some final tweaks where needed, like short names for tables and fields (weird mania, I know) and color/fonts tweaks, but I've never complained about missing functionality.
Now about the wiring, I believe, from the docs [1] (The DeepSeek API uses an API format compatible with OpenAI/Anthropic), they all use the same standard for communicating with the LLM, so they're all pluggable.
[1] https://api-docs.deepseek.com