I would not write a complex technical paper in Org Mode, other than just to get my thoughts together initially to eventually copy/paste into LaTeX.
But, Org Mode is good enough for most of my writing over the last several years. It is more readable as plain text, and exports to HTML or PDF trivially (the latter via the LaTeX export hook). I like it enough that I use it as the basis of my blog, exporting each article to HTML and then massaging the HTML programmatically to generate static files styled and cross-linked the way I want. This approach gives me math formulas via MathJax, still images, tables, code snippets... basically everything I want for a somewhat tech-y blog.
But, yeah, if you're going to just write a full-on technical paper for publication, I'd go right to LaTeX.