I started using ConTeXt (http://wiki.contextgarden.net/Main_Page) after many years of LaTeX. The command interfaces are more homogeneous than with LaTeX and it is quite easy to do complex layout with it.
ConTeXt is an awesome package. Its "only" drawback is that it's unsupported by publishers. I thought about writing my thesis in ConTeXt, but then I couldn't have easily reused the text from published papers.