I use both regularly. Google assistant is far superior, coming in at annoyingly bad compared to Sirius infuriatingly bad.

Gotta say I'm not especially impressed with my Google assistant on my pixel either. The hit rate makes it worthwhile only when I have to use it.

I’ve used Android phones in the past, and Google’s tube person. Siri has IMO clearly gotten worse over time, on both my phone and my HomePods. I wouldn’t be surprised if Google is better at this point.