Two separate currencies is the common complaint: 3,000 basic words and 1,000 advanced words a month are not interchangeable, so the number you care about is whichever runs out first, and it is rarely obvious in advance.
The 500-word per-request cap is the other one. It is the tightest entry-tier limit of any tool on this page, and it makes long-document work a chore regardless of how much monthly allowance is left.
Worth knowing before you go: the cap lifts sharply higher up. Pro takes 1,200 words per run and the Unlimited tier removes the input limit entirely, both at $9.99 a month billed annually. If the 500-word ceiling is the only thing driving you off, moving up one tier is cheaper than moving out.
None of that makes Humbot a bad tool. It makes it a tool with a shape, and the question is whether that shape matches your work. Our full HumanFlow vs Humbot comparison sets its numbers against ours in detail, including where Humbot wins.