On Linux, and to a slightly lesser extent on Windows and Mac, TeX Live is the de-facto TeX distribution. However, TeX Live is not satisfactory to a ConTeXt user because the updates on TeX Live are slow. Only stable releases of ConTeXt are synced with TeX Live, while ConTeXt users are accustomed to the almost daily beta releases of ConTeXt. (So much so that if ConTeXt is not updated for a few days, users think that something is wrong with their setup).
An alternative TeX distribution for ConTeXt is ConTeXt Minimals. Its name, and motto, should not be confused with minimalism. On the contrary, ConTeXt minimals contains everything needed to run ConTeXt (well everything except ruby, which is used by MkII scripts) and once installed, it occupies a good 200MB disk space. It is minimal in the sense that if you took away anything from it, some functionality of ConTeXt would be crippled.