Quillstack does the job and will not tell you what it costs
Eleven weeks in, Quillstack does the central thing well: text goes in, and people who did not write it can find it. That sounds low as a bar. Most tools in this category fail it, because search is treated as a feature rather than the product.
Onboarding took under an hour for four people, none of whom asked a question afterwards. Support answered twice in under a day and once not at all.
Pricing is where this falls down and the score reflects it heavily. The advertised seat price does not include the usage that any real team generates, and the metered rate is not published. A tool you cannot budget for is a tool you will eventually leave, and the export path out of Quillstack is partial, which is what pushes the switching-cost score down rather than up.