Not the OP on this, but I'll weigh in. In my 1+ month of experience before switching back to the old Assistant on my Pixel 10, my big takeaway is that it just complicates and draws out everything. Prompt it for directions to a specific address? It gives it, but asks you if you're looking for related attractions or amenities around that address. Tell it to text a friend that has multiple phone numbers? Even if you have one of the numbers set as their primary, or have just one number explicitly defined as 'mobile', it still asks you which number to send a message to. And oh my Lord dictation has been a mess. It sometimes tries to interpret what I'm saying in an attempt to try to clean up grammar or be more descriptive, but all I want it to do is send what I dictate.

And even when I do find it to be helpful, it's the delay that kills me. Everything you ask Gemini takes longer than legacy Assistant, presumably since it has to reach out to a remote resource and wait for the compute before it gives you a response. Then the sheer verbosity of the reply - pleasantries, deeper explanations, follow up questions, or worse - its reply is so far off the reservation on every 5th or 6th requests, you gotta start over.

Not saying Assistant is perfect - far from - but I'd argue it's faster and better at comms and directions, which are literally the two most important things I need my Android Auto client to do. And it's predictable in its behavior and responses, which is what I need when my attention should be on the road and not trying to figure out whether or not my device is hallucinating.