Beginning work without a contract was certainly not a smart move. They talked a good game but I still should have known better. However, I think I was still in a pretty good position, because it is that contract that gave them the right to use my work. I already had a reasonably popular technical blog that would have made a fine home for what I wrote if they had changed their minds.
In fact, this gave me quite a bit of leverage when it came time to get the Pro Objective-C contract amended. After they refused my amendments, I pointed out that they could not use my work without a contract, and that I would not sign anything that didn't have my amendments. They changed their tune with amusing rapidity.
The amendments I requested were fairly simple. Aside from fixing the dates, I struck out portions that required ongoing work from me, such as responding to errata, since I was no longer involved with the book.
The money involved was not large, for sure. In general, writing technical books doesn't pay well. There are good reasons to do it (exposure, fun, satisfaction, etc.) but money isn't one. I went into the project knowing that I wasn't doing it for the money. Given that, it might seem strange to have such a problem over money, but I don't think it is: even though I wasn't doing it for the money, I was still promised money, and I simply couldn't tolerate any crap over it.
For everyone talking about other publishers, I appreciate the sentiment, but I have moved into self-publishing. The Complete Friday Q&A is self-published and the experience was great. I intend to continue doing so in the future. I really don't see much of a role for traditional publishers these days.