MCC is a hex dump that most players, and people, cannot read. SRT is accepted by practically every player, site and editor. MCC is at home in closed captions for broadcast and streaming delivery that carry CEA-708 as well as CEA-608; SRT is the usual choice for subtitles that must work almost everywhere.
The text is read as UTF-8 or UTF-16, whichever the file is. An older file in another code page is read using the charset it declares, or as Windows-1252 if it declares none, so accented letters in an unlabelled legacy file can come out wrong. A file that is not text, such as the picture-based subtitles of a DVD, is refused instead of being converted to nonsense. Of the styling, only italic, bold, underline and the position on screen (top, middle or bottom, left, centre or right) travel between formats; fonts, colours, outlines and effects do not. The CEA-608 caption data inside each packet is read, as for SCC. Captions that exist only as CEA-708 service data are not read. Positioned lines are written with {\an} codes, which many players honour; players that do not simply show them at the bottom.