The ATFS-1 Foot Switch is designed to be lightweight and ultra compact.  Constructed of a single piece of molded polycarbonate that's nearly indestructible,  the ATFS-1 is an ideal foot switch for people who are concerned with portability and being able to carry accessories around with a minimum of fuss.  The ATFS-1 is designed for optimal use on flat surfaces, such as wooden stage floors and low carpets.  Due to its light weight, it is not ideally suited for uneven surfaces.

The ATFS-1 features a very low profile, making it easy to tap with a minimum of effort.

The Boss FS-5U Foot Switch features a rugged design and a rubber base.  Multiple FS-5U foot switches can be locked together, thanks to a tongue and groove design along the sides.  If you need to frequently turn pages forwards and backwards, you may find the locking design more comfortable.  The FS-5U is heavier and bulkier than the ATFS-1, making it more unwieldy to carry around, but better suited for uneven surfaces (like brick floors or heavy shag carpeting).

The FS-5U has a higher profile than the ATFS-1 as well as a smaller tapping surface.