Going via traditional publishing is a fools game. The author says you can get $10,000, but for most my books, publishers would only pay $2000. And even that amount is paid over 1-2 years. And he's right about publishers trying sleazy things. Another thing they may ask for is "All future rights in any medium". So people who signed this clause in 90's/early 2000s lost right of their ebook/audiobooks, which are the most…
That depends very strongly on the publisher, and if you go with one of the industry leaders than it can be a very useful decision to go the traditional publishing route.
No Starch and Manning are both excellent publishers with fantastic teams. You'll get lots of attention from experienced editors, teams of talented people assisting you throughout that process, and very nice distribution channels. I've known many authors that have worked with these publishers and none of them have regretted it.
If you purely care about the money, then I think self publishing for a niche audience is probably the best route, though you have to put some extra energy into marketing. The math just works out that much higher royalties on a smaller audience means more direct income.
But if you want to make a really excellent book, and would like to be able to walk in to a Barnes and Noble and see it on the shelf, then going with an experienced, quality publisher can make a notable difference.