As someone who writes for Packt (Posting under a throwaway for obvious reasons), I think you made the right decision. The first title I was proud of, had good editorial control and decent technical review. The second title had an awful premise that was insisted upon and stunningly poor editorial control. Disappointingly I now feel like I have to apologise for something that carries my name.

My next title will be self-published onto Github on a 'freemium' model. It'll allow me to develop the content in the open, and if people are so disposed, they can pay for an edition that carries additional explanatory text. Either way, I won't be writing for Packt again.

When I worked at ThoughtWorks, I also got approached by them, and told my sponsor and colleague about it. Then the horror stories came, and mostly about the time pressure they put on you and the miserable pay-off. Most of the time you will be rewarded with give-away copies...