The Force Gauge most often uses a strain gauge load cell to measure the amplitude of the force vector, and this is more consistent with industrial types of weigh Scales, which are of a somewhat reduced accuracy.  The strain gauge load cell is a more robust and much lighter and less complicated device, and is much better suited to the force gauge application.  
Force Gauges may be single capacity devices, where they have a single built in strain gauge load cell, or they may use interchangeable strain gauges that allow them to change their measurement capacity over a wide range.  They are also capable of measuring rotational forces (torque) with special adapters.  They also may be mounted in special stands that allow the measurement of displacement with the application of force (that is measured by the force gauge) and this makes them capable of all kinds of stress testing, including hardness tests.

There are Force Gauges that are based upon simpler principles that are very valuable in special applications.  Some are based upon calibrated springs and have dial type readouts that make them less expensive and easy to use.  The Force Gauge based upon strain gauge technology usually have a digital display that may be LCD (liquid crystal display) with segmented digits, or they may have an advanced LED (light emitting diode) graphics type display based upon pixels that allows more complex displays such as X-Y plots.

Because many of these devices are used in production control and quality control applications where they are not treated with the same care we might expect in a laboratory, they must be rugged and easily cleaned.  It often is a lot cheaper in the long run to buy the best available from the start.  Flexibility may be a major consideration if the gauge is to be used in a variety of applications.  Data storage and transfer may also be a serious consideration in making a choice between gauges.  If the gauge is to be used as a hand held (and many are) then weight and ease of readout become serious factors.  If used as a portable handheld device it will require that its batteries be of sufficient capacity for the application and that recharging is simple and safe.
Do your homework before you invest in a Force Gauge, it will almost always prove to be well worth the time spent.