On PC systems, there are a variety of WYSIWIG editors. They have an obvious advantage over (La)TeX, but if your thesis has a significant amount of mathematical equations in it, you'll be much better off using (La)TeX. I have yet to see anything else that can format math as well; the second best isn'y even close.
Also, be aware that there are thesis templates for LaTeX; for other text formatters, you'll be on your own.
If you don't know either TeX or LaTeX, ignore the annoying people who have passed the enourmous learning curve to learn TeX: as annoying as it is, LaTeX is much easier to learn.