They're exactly equivalent. As for endianness, it depends on what you're reading. Normally, it will be a buffer of bytes, which you'll then have to "unformat", according to the format with which they were written. And since it's bytes, endianness plays no role.
EDIT:
As simonc pointed out (and then deleted, because he didn't get it 100% right---but his point was valid): there is a difference with regards to the return value (which you need to use in order to know whether the function worked or not). fread( buffer, 8192, 1, fp ) will return either 0 or 1, and 1 only if all 8192 bytes have been read. In addition, Posix says that the contents of the buffer are not specified for partially read objects. In practice, the buffer will have been filled with as many bytes as could be read, but since you don't know how many that was, that doesn't buy you much. In sum, you should always use fread( buffer, 1, 8192, fp ); (since it makes no sense to use this function for anything but a buffer of bytes).
