Like others have said, there are pros and cons to both. From my experience, working with a publisher was exactly what I needed, and it's worked out very well. I published a moderately successful technical book (my second book, the first one was awful and sold poorly, the publisher was terrible, but the experience was good to have) a little over a year ago, and, not only has it made me well over $40k in royalties, but it's been bought by foreign publishers and has been released in several other languages as well, and royalties have actually increased in recent months because of foreign releases.

Sort of a point-by-point take on my perspective of the author's main points in his blog post:

I own the copyright to both my books. Didn't have to ask for it, didn't really care, but it seems to be pretty standard among publishers (although I could be very wrong about that, and just lucky). Honestly, I didn't really care about owning the copyright. It doesn't affect my day-to-day life. I've heard of sketchy publishers taking an author's content, re-writing it, publishing under someone else's name, or re-using it in weird ways, but that's not really an issue with my contract, and shouldn't be an issue with any reputable publisher.

Writing for fun? It was fun! Sort of. It was a lot of really intense work, and late nights. But I enjoy the subject immensely. If you write a technical book, money should be a very very low priority -- it's a nice surprise at the end, the icing on the cake. So who the money is going to, or in what percentage, shouldn't affect your motivations or the "fun" you have doing it either way. It really didn't feel like "working for someone else" at all, it felt like it was entirely my project, but I had an excellent support team to help me out if I needed it.

The ability to update whenever you want? Sounds like a bunch of maintenance work pressure. The book was analyzed by technical editors, copy editors, layout people, illustrators, and god-knows-what-else to death before its release. It was stamped with the ISBN number, preserved in the Library of Congress, and it's done. Although I did some additional (optional) editing when foreign translators gave some feedback, I don't have to do anything else until (if) I decide to write a second edition. It's not a constant side project, I don't have to track sales, I don't have to advertise, it's not something I think about much, I just watch my bank account get a big boost once in a while, and send the IRS money every quarter. The publisher sets up book signings and talks once in a while, but those are totally optional, and it's kind of a nice tax write off weekend vacation for me, and I turn them down as often as I go to them. "San Francisco for a week?" Ehh. "Las Vegas for the weekend?" Yes please.

Advanced sales analytics? Sweet summer child, I have a publisher to worry about stuff like that. If I cared (which I only did in the first month or two of sales, before I realized there were more important things in life, like drinking and watching Netflix), I can call them up and get as many gory details and spreadsheets as I want. So really, I feel like I have the best of both worlds.

Money: Yes, it's sometimes a little nuts to see that my publisher has made 6 figures off this book and I'm sitting around saying "Sweet! Another $3k in my bank account!" But I make 25% off of online sales (and licensing, and a few other things) and 10% off of hard copy revenue, so life isn't really that bad. The last time I had to do anything with the book was a year ago, the publisher's probably put more work into it than I have at this point, and they have an amazing network of resources to promote it. My book is in libraries, bookstores, sold at conferences -- and I don't have to do a damn thing to get it there. Colleges that wouldn't even admit me have my book in their library! Sometimes I google "<name of book> syllabus <year>" to see what kind of professors are using it for required reading this semester.

I might seem a little aloof, but don't get me wrong, I LOVE my book, and am extremely attached to it. But, sometimes, you children have to grow up and leave the home, and I'm happy to pay my publisher to allow it to do that. So, if you like ongoing projects, and are an entrepreneurial self-promoting type, definitely self-publish. But I'm not an entrepreneur. I'm have some writing experience, professional teaching experience, and am a full-time software engineer, but not all of us have to want to start our own business to get a book out there.