Link Details

I've read books from both publishers.....my preference is Manning. The only gripe I have about Manning is the covers of the books....but it could be worse, have you seen the covers of the "Head First" series of books? The "Head First" series of books are great reads, but I am too embarrassed by their covers to bring them to work (i.e. a professional environment.

Regards,
Tom

A posted my thoughts (and a little experiment) on this topic in my blog at http://charteo.us/the-oreilly-and-manning-debate. You can read the details there but here is the conclusion: Manning books are more popular (being bought and read by more people) than competitive titles from O'Reilly.

I was approached by both publishers to write a book on iText ( http://itext.ugent.be/itext-in-action/ ). Eventually I chose to write for Manning. It may be interesting to explain why.

It was certainly an important factor that I had developed a slight preference for Manning books over O'Reilly books over the last few years. I really like O'Reilly books too, not in the least because I thank a lot to O'Reilly books when I first started my career in the IT world.
However when I talked with a professor (Geert De Soete) at Ghent University (my employer) who had been following iText since the very beginning, he said: "Look Bruno, you have never written a book before, and a first book is very important. You must make sure you don't fail."
I said, OK, now he's going to express his doubts about my writing capabilities, but no: he asked a question. He asked: "How many books does O'Reilly publish a year?"
I replied: "I don't know, maybe 500?"
Then he said: "Could be. Now how many books does Manning publish?"
I answered: "Er... maybe 50?"
He said: "I don't know the exact figures any more than you do, but the ratio is probably about right. Now answer this: which publisher has the most interest in making your book a success?"

It made me think: if I write a book for O'Reilly, and it fails, then this probably won't hurt O'Reilly much, because they have 499 other titles that can be successful. However, if I write a book for Manning, the publisher only has 49 other titles to reduce the loss in case of me failing. Therefore, it must be in the best interest of Manning to help me make my book a success.
So I answered to my professor: "OK, I understand, I'll go for Manning Publications."
I'm sure I have regretted this decision at times, while I was writing the book, because they are very demanding at Manning and they really 'work' their authors. But I can't deny that they also provided me with a whole team of editors and coaches supporting me during the writing process, and when I wasn't comfortable with one coach, they replaced him/her, no questions asked.
When I look back at that period, and certainly when I look at the finished product, I'm sure I made the right decision choosing Manning.

Surely, if I could do it all over right now, there are plenty of things I would have done differently, but I think that's only normal. After all, it's good to have some ideas in store for a second book ;-)
For my first book, I wasn't really interested in 'making a lot of money', my main concern was to be able to bring the book project to a good end; the quality of the book was most important to me.
You mustn't forget that, even if the book only has one name on the cover, it is essentially the product of a whole team. Reading what Norman says about 'already having a relationship with O'Reilly', I'm not sure if any other Publisher would have invested in me, a first-time writer without any writing experience, the way Manning has.
You can't know in advance if you will get that kind of support, but another factor that was important for me, was the fact that many Manning books about specific technologies are actually (co-)written by the founders and/or project leaders of those projects. That's another question the professor could have asked me: "do you think Manning would be able to contract these people if they weren't able to offer sufficient quality?"

Hell, I sound like a walking, talking promotion machine for Manning. Was I brainwashed during the 18 months I worked for them? Maybe; I can't compare with O'Reilly like Norman does in his article, but I just wanted to say that my experience with Manning was a very positive one.