I have used all three and I can invariably state the differences between them. When it comes to an AI tool that can easily generate summaries and anything that has to do with texts and creative writing among the 3, Chat GPT wins it.
If you want information in real time, Grok wins it here. It can give you information about something that just happened minutes ago.
If you want objective information that is always balanced at a higher degree, Claude AI wins it. It doesn't have biases.