I used to use Help & Manual and before that Help n’Doc I think it was called. The problem I’ve always found with traditional help files — online and offline — is that the vast majority of users will never read them. The dry format and in depth nature of the content is an actual deterrence for the average user. For technical products with a technical user, that’s different — but not by much.
The approach I now take is to structure “Help” sections more like a Blog, with a series of posts that describe a particular part of the product or workflow — with some crossover and duplication between posts. This is far more readable for users, and a lot of them actually do read these posts, or at least dip into them. It’s not about documenting every button or menu, it’s about informing the user so they can do what they need to do.
The content is simply static pages on the product website — I don’t see why a SaaS would come into play here at all.