Kevin Indig ran 20,000 prompts across ChatGPT, Perplexity and Google AI Overviews. Only 2.37% of cited URLs turned up on all three for the same prompt, and 91.07% appeared on one engine and nowhere else.

I went through the main players for a market map I've been building for Ghostart to compare price and functionality.

There are more players, of course (I've reviewed over 40 Ghostart competitors), but I've cherry picked the main ones:

Free AI Visibility measurement

Free, or bundled into hosting you already pay for. None of these generate content and none give you prioritised recommendations. Measurement visibility only.

• Bing Webmaster Tools — Copilot and Bing AI answers, plus partner integrations Microsoft doesn't name. No Gemini.
• Google Search Console — the generative AI report is impressions only. No clicks, no position, no query data.
• HubSpot AI Search Grader — 3 engines, one-time check, no account needed.
• Squarespace — ChatGPT and Gemini, metered against your plan's AI credits. 7.1 sites, English only.
• Wix — 3 engines, and it wants 50+ unique visitors in 30 days before it shows you anything.

HubSpot draws the line between free and paid openly: the score is free, the prioritised to-do list version is $50 a month.

Paid measurement

More depth than the free tools, still measurement only.

• Rankscale $20 — the Pro card names 10 engines; the entry tier's coverage isn't published
• Otterly Lite $29 — 4 engines, 15 prompts
• Knowatoa $59 — 3 of 7 engines
• Waikay $69.95 — 4 engines, 120 prompts
• Peec AI €85, or €70 annual — 3 of 6 models, 50 prompts
• Profound Starter $99, or $82.50 annual — ChatGPT only, 50 prompts
• AthenaHQ $295 — 8 named models

Measurement plus a GEO to-do list

• HubSpot AEO $50, or $45 annual — 3 engines, no Claude, 25 prompts
• Semrush $139, or $117 annual — 6 engines, and AI visibility is bundled into every tier
• Surfer AI Search Analytics $158, annual only — 5 engines, 100 prompts

Measurement plus writing the page

• Frase $49, or $39 annual — 2 engines, one site, one seat
• Jasper Pro $69 — GEO sits in the Business tier, so you can't buy it on this plan at any price
• Sitecore $300, or $250 annual — 6 engines, since it bought Scrunch
• seoClarity and Conductor AgentStack — enterprise, no public price

AI Visibility / GEO - the full loop

These tools do what the free measurement tools do, but with an added 'to do' list for fixing things AND ability to create the content AND ongoing content recommendations and monitoring.

They measure AI Visibility, find your gaps, publish something that fills them, then check whether anything moves over time.

• Ghostart $79 annual — 4 AI engines at entry, 6 above it
• Writesonic $79 annual — 3 engines on every self-serve tier
• Adobe LLM Optimizer — enterprise

Considerations

At $99 a month, Profound gives you one engine and Ghostart gives you four, Writesonic three. Ghostart and Writesonic are the same price at every tier.

Chen et al. at the University of Toronto ran a study across 300 consumer-electronics queries, when someone asks an AI a consideration-stage question — the sort where they're working out who to shortlist — earned sources supply 59 to 86% of the citations.

Your own site wins the transactional questions instead, at 52 to 68%.

Almost everything on the list above works on the site you own. Ghostart also cross-references the coverage you've earned, press mentions, guest articles, directory listings and reviews, against the URLs the engines actually cite.

Sources

Kevin Indig, The Consensus Gap · Chen, Wang, Chen and Koudas, University of Toronto, arXiv:2601.16858 · Schulte, Bleeker and Kaufmann, University of St. Gallen, arXiv:2604.07585 · Fishkin and O'Donnell, SparkToro, and Search Engine Land's report of it

Prices verified against vendor pricing pages, 11 August 2026.