What is the main difference between Google now and Google assistant? I've had Google assistant for a few days now and yet to use it.
Assistant is an evolution of Now/On Tap. First... the most obvious change is the interface when you launch the On Tap/Screen Search interface. Previously, it would give you a list of action icons.. stuff like finding a gas station or ATM, etc. Then it would search your screen and try to give you relevant information based on that. With Assistant, it alters the interface, moving to a voice based system rather than a touch based.
The second main difference is a little bit more subtle and has to do with the voice interaction. With Now, it was relatively basic.... it would transcribe your query into a direct Google search and give you results. There were some commands, but they were a bit rigid and you had to know them to use them.
With Assistant, Google enhanced things... rather that it transcribing your query into a Google search, it attempts to understand you in a more conversational tone. It is more able to interact with you when you use natural speech, and then also retains context. So when you ask "Are there any Thai restaurants near me?" After it gives you a list, you ask "When does it open?" and it will understand.
Assistant attempts to improve on what a lot of people complain about.... rather than dictating commands, people want to speak in a natural way without having to memorize particular syntax and commands.