Tracking AI visibility is fraught with bias, since there's nothing like Google Search Console to provide real-world data. Essentially, every product is relying on tracking visibility across a set of prompts (with some interesting complementary analytics such as tracking AI-agent visits to your page on user's behalf).
While we didn't go through the onboarding/prompt generation process for any competitors, Gauge's onboarding process seemed so high quality that we didn't feel the need to. It has an agent that performs market research, and uses actual search terms (and their rough search volume) to generate a very diverse set of prompts that appeared, to us, to be a very good representative set.
Their team is (currently) small, and the product is evolving quickly, but don't let that be a deterrent. There were several times when we asked for bespoke features, and had them deliver on them in a 1-2 day turnaround.
Gauge