If you're a general user or a developer who values a wide range of features—including chat, images, and voice functionality—go with ChatGPT. Its broad feature set and strong ecosystem of integrations make it suitable for various tasks. However, if you're focused on affordability for high-volume API usage, ChatGPT's "mini" models can be a cost-effective solution, though be mindful of its closed model structure.
On the other hand, choose Ollama if you’re a developer or part of a team and want a straightforward way to build with open models. Its easy setup and flexibility with deployment options shine in cloud-based settings. However, keep in mind that Ollama lacks a free tier and has limited offline capabilities, so it's not the best fit if you seek a free solution or need extensive offline access.