More than one company's models
ChatGPT gives you OpenAI's models. That is the point of it, and they are good. But some days the better answer comes from Claude or Gemini, and you cannot get to those from inside ChatGPT.
Unium puts the leading models from several providers in one app, so the model is a choice you make per message rather than a company you committed to. You can even ask a few of them the same question and compare the answers.
Pay for what you use, not a flat monthly fee
ChatGPT Plus is a fixed monthly subscription. If you use it every day, that is fair value. If you use it in bursts, a heavy week and then nothing for a while, you are paying through the quiet stretches.
Unium is pay as you go. Sign up free, top up prepaid credits, and spend them only when you run a paid model or tool. A quiet month barely costs anything, and credits stay valid for up to a year.
Built for more than one person
A ChatGPT account is yours alone. Sharing an answer means a screenshot, which drops all the context the model had.
Unium lets you share the actual chat so someone else can read and continue it, and pool credits in a shared wallet so a family or small team works from one balance instead of buying a plan each.
When ChatGPT is still the right call
To be fair about it: if you are happy on OpenAI's models, you use it daily, and you only ever need it for yourself, a single subscription is simple and there is no strong reason to move. Unium earns its place when you want more than one provider, lumpy pay-as-you-go billing, or more than one person on the same balance. If that is you, the pricing page shows how the credits work.