That rather despicable man, Arthur Koestler, once said that a publisher who wrote was like a cow in a milk bar. This has never struck me as a very elegant simile but it does point to the very real conflict which can be caused by combining the two roles. As both a writer and a publisher, I find that the tools which I want for one role are often unsuited for use in the other role. For print publishing and, to a lesser extent, ePub and Kindle publishing, Adobe InDesign is the program of choice. It has the best typographical control and the best built-in indexing software. It produces trouble-free PDFs which can be tailored to the printers' requirements and, with a bit of hard work, can export good ePubs and Kindle books. As a medium for writing, however, it leaves much to be desired.
InDesign is a large, ponderous program which is slow to start up, heavy on resources and almost incapable of exporting even the humblest of rtf files. Perhaps more seriously, at least for those with typographical leanings, is that it is an obsessively visual program, diverting one's mind away from the substance of a writer's work. I have no wish to revert to a manual typewriter, although there is much to be said for writing first drafts in longhand and then typing into a computer, so some sort of program is required.
Some swear by Microsoft Word but I am more likely to swear at it. Word, like InDesign, is large and cumbersome, partly because, like Apple's Pages program (long due an overhaul), it has aspirations to be more than a word processor. On the Mac, a far better word processor is Nisus Writer Pro (or the slightly cut-down Nisus Writer Express). These are good, old-fashion programs which concentrate on handling words not pictures, drop caps and ligated characters. If one is obsessed with function over form, Ulysses offers syntactic mark-up, an idea not unlike creating an XML file without the complexity of an XML editor. For most people, however, especially creative writers, this formal approach is inimical to the writing process.
Ulysses is one of those writing programs, which date back at least to LaTeX, in which a single document consists of many files. This approach offers many advantages in terms of planning and organisation. For the novelist, there is Story Mill and, now a similar French program, Jécris un Roman. Although very good, Story Mill seems to be aimed at writers who have attended writing courses and have learnt a rather formulaic approach. It is also unsuited to non-fiction authorship. I haven't tried Jécris un Roman but I suspect that the same applies. My own favourite writing program at the moment is Scrivener which is equally suited to fiction and non-fiction and is very good at organising both text and reference materials.
I recently upgraded to Mountain Lion with absolutely no problems. I was delighted to discover the included Dictation program which works surprisingly well.