mp4/h.264 is not a production codec, but an output codec. In other words, it takes a very long time to write, and it is very lossy. In addition, it takes some system resources to play it back. it is ideal for deployment on the web etc, since many many devices can play back mp4/h.264, and it is pretty efficient to reduce the data (lossy) to a manageable file size (up to 4k in resolution).
Apple ProRes is a production codec, it has only very limited loss (and creates huge files), and writes and reads very fast. Ideal for post production, jumping from one part of the editing to the next one without loosing much time. (it can also take any pixel size you can imagine). There is no real equivalent to apple prores under windows, afaik, but I am sure there are useful alternatives (avi, mov) available. it is a great format to use for image sequence output from AVP, and convert to mov (apple prores) for editing/grading/compositing. if you don't need to create a full res master, don't need much to edit, you can go straight from image sequence to 2k/4k mp4/h264 in your editing application.