My previous provider charged me 450 €/month for 270 prompts. ZeroRank gives me 2,400 prompts, for life, for less than three months of that bill. That's the whole review, really; but I'll add that Kelvin's client service is excellent and he actually listens when you suggest improvements. If you're working in AEO, GEO, AI SEO, or whatever the next acronym turns out to be, this is a straightforward buy.