GPT-3.5 (the free version) is best used in a creative sense - getting it to create tests and flashcards, writing emails, articles, plans. However, it has no information past Jan 2022. GPT-4 (only accessible through the paid version) is a lot more useful - it has access to the internet, it can be used with other "GPTs" which mean it can be used for a huge variety of different tasks, and has an image generator (Dall-E).
Claude has recently been updated, with it's current performance surpassing Chat GPT in most areas. Like Chat GPT, it is great for creative tasks, but also does not have up-to-date information.
Perplexity is an amazing tool for research, and day-to-day use. It provides sources for all of its information, and so is amazing at finding information that would normally take time to find through Google.
Microsoft Copilot is a great tool for a variety of functions - it can browse the internet, generate images, and will provide links with every answer that it gives.
Leonardo is just a very simple, and very good, image generator, which will just generate a prompt based on the prompt you put into it. It also has the ability to change it's art style.
Midjourney is a more advanced image generator. It is harder to get it to generate amazing pictures, but once you figure out how to prompt it in the right way, it can produce great results.
