Agreed. My first tech book was done in MS Word 6 (yeah, it was a long time ago). It was a nightmare. We had several production problems when it was time to produce the PostScript to send to the pre-press machine. Ugh.
The next books were done in LaTeX (my editor insisted on it for the 1st one, then I was sold). Sure, it's a bit of a learning curve, but the flexibility and control given by LaTeX are worth learning the tricks. Plus, Lamport's LaTex book is actually a well-written tutorial. Aspiring tech books authors would be well inspired to study its style and organization.
LyX reportedly goes a long way to making LaTeX easier to use. I haven't used it myself, though.