If that is your priority, there is no need to look further. Because maintaining a manual in the same system where support discussions take place is arguably the easiest. And as regards formatting, discourse is very flexible as it supports Markdown, BBCode, and simple HTML.
But I understand your urge to compate products. I am also a comparer (though I have less and less time for that). So if you want to compare products, I’d suggest that you include discourse in your list of products. I have so far based my recommendation on the criteria that you mentioned (plus two of my own). It is entirely possible that discourse will not do as good if you add other criteria. So once you have those criteria, I’ll be happy to revise my recommendation.
If you’re wondering about whether discourse can do something, let me know.