Colab Pro is my favorite for day-to-day development needs, but I also love keeping a VS Code workspace always open and ready to quickly test ideas.
And my general workflow. I develop and varify my model can learn with the setup described above, then I clean and convert my code into a Python package using VS Code and push it into a private repo. Now I can easily go serverless for training with Cloud AI Platform (and Cloud TPU for giant networks). I always try to make TensorFlow IO API the only dependency for my data pipeline, which boosts the portability to different filesystems and accelerators