There are two deficiencies on a fryer with mechanical thermostatic control

The technology of temperature sensor

In the food industry, a mechanical thermostat is generally considered accurate if its tolerance is +/- 5 deg C in the cooking range of 170 deg C, whereas a Brandon computer control fryer with thermistor sensor has a temperature tolerance of +/- 1 deg C.   A computer control fryer is far more accurate.

Temperature overshoot

In addition to thermostatic accuracy, fryer of mechanical thermostat has a temperature overshoot issue.  A mechanical fryer will not stop heating until the oil temperature reaches its set point.  Residual heat due to the thermal mass of the heating element will eventually dissipate to the cooking oil, leading to a temperature overshoot.    In our own experience, it is not uncommon to see temperature overshoot of over 7 deg C.   Depending on the type of food you are cooking, such deviation in cooking temperature may translate into food quality fluctuation.

In the firmware of a Brandon computer control fryer, a function is built in to calculate whether the slope of temperature rise will lead to an overshoot.   When it anticipates an overshoot, it will reduce the power supplied to the heating element, effectively reducing the slope of the temperature rise and thus lessen the impact of overshoot to the minimum.

Analogy of braking a car

Let's imagine how a driver brakes his car in two scenarios

In a mechanical fryer, the driver is like driving ahead at full steam, and only presses hard on the car brake at the instant of crossing the stop line of the traffic light.   At such momentum, it takes the car almost a hundred meter beyond the stop line to come to a halt.

A computer control fryer is like a driver seeing the traffic light from a distance.  Anticipating that his car may not stop in time, he presses the brake softly to reduce the car speed and finally manages to stop it just a few meter before the stop line.

Meeting the expectation of your customer

Customers have different expectation when they patronize your restaurant.   They may be attracted by the service of your staff,  the decor of your restaurant or the food you serve.  Almost a decade ago I had a chance of visiting a restaurant in Guilin, China known for baking pizza in traditional way.  They used a masonry cookstove heated with charcoal fire.   There was no control on the oven.  Apparently, the chef had to be skillful to be able to cook good pizza with such a basic stove.  The restaurant decor was nostalgic and staff were friendly.   Years on, I can still remember the laughter of my wife and sons, and how attentively they watched the chef doing his magic.    It is absolutely a good restaurant.  Alright, I admit that I forgot how the pizza tasted, but does it matter?

If, however, your restaurant is known for serving good food, your kitchen staff deserve to have good equipment to do their job.   That said, a computer control fryer is essential to satisfy your customer.