I've been working a few weeks on really polishing up a proposal and content for a computer book aimed at an intermediate skill level on an accessible topic. During my search for publishers to submit the proposal to once it is ready, I have come across the following ones:
O'Reilly group: No Starch Press, O'Reilly, Paraglyph, PC Publishing, Pragmatic Bookshelf, Rocky Nook, SitePoint, TidBITS)
InformIT group: including Que and Sams Publishing, Peachpit, etc.
Sybex (associated with Wiley)
In any case, I have a couple of simple questions: does anyone know of any major publishers of this kind of book that I have missed? Can anyone here who has submitted a proposal, and/or published with any of them, share any brief tips/experiences? Finally, and I know this depends on a lot of factors, does anyone know of a resource to find additional possible publishers with? I know of the Writer's Market, but I gather that's aimed more toward fictional works.
EDIT to add: Are there any that you have heard horror stories about that I have listed here?