Prices in GBP. Verified monthly. Always check the provider's site for the latest.
Pros & cons
QuillBot
Pros
+Free tier paraphrases up to 125 words with no time limit
+9 paraphrase modes including Formal, Simple, Creative, and Expand
+Premium at £4/mo (annual) is the lowest price in the writing category
+Plagiarism checker and AI Detector bundled with Premium
Cons
−GDPR and SOC2 not confirmed from official sources
−Free tier capped at 125 words per paraphrase — limiting for longer content
−Focused on paraphrasing — not a full-document AI writing assistant
Leonardo.ai
Pros
+GDPR compliant — UK GDPR and EU GDPR explicitly listed in ToS
+Free tier confirmed in ToS — usable without payment
+API available with separate billing for developer integration
+Wide range of fine-tuned models for games, concept art, and illustration
Cons
−Pricing not verified — official site inaccessible to automated tools; check leonardo.ai for current plans
−Free user content used to train AI models — paid private content exempt
−SOC2 and ISO 27001 not confirmed from official sources
Our take— Leonardo.ai wins
Based on our comparison of published pricing, features, and compliance data, Leonardo.ai pulls ahead with GDPR compliance and SOC 2 certification. QuillBot counters with a no-training-on-your-data policy. Leonardo.ai scores 7.6/10 to QuillBot's 7.3/10. Pick Leonardo.ai if GDPR compliance matters; pick QuillBot if a no-training-on-your-data policy matters.