Text Only printing lets you send the file directly to the printer, bypassing the Windows printer driver.
This is only really useful for printing *text* files, as V will try to paginate the files. That is, start a new page depending on how many lines in a page.
Raw/Binary printing, however, does not paginate the file. It sends the file unmodified to the printer.
Raw/Binary printing can be used to print a file that already contains printer control codes, and needs to bypass the printer driver in order to print correctly.