Front feed uses rubber rollers to bring the top sheet from the tray into the printer. The tray for new sheets is placed in front of the printer, requiring more desk space. Whereas Top feed printers feed the paper down into the printer and hence they don't require as much space. This refers to the maximum number of pages that can be stored in the printer before refilling it. A larger capacity tray allows you to leave the printer unattended for longer period of time.
Postscript is a more complex language and is used in printers that handle complex graphics.
Are fonts built into the printer. Resident fonts can be printed quickly by the printer at very high resolutions. Zoom feature allows you to enlarge and reduce copies. This is useful when you only need part of a piece of paper or when you re going from one size paper to another.