Having been forced by different circumstances to almost simultaneously replace both a cooker and a deep fryer, both gave reasons to suspect that the temperatures available were not as they should be. The cooker oven claimed that its temperature settings were 1-1½ Gas Mark equivalents higher than is normal. For several cakes which are time/temperature dependant, they were not cooking as well as quickly as expected. I needed reassurance and this was it; although not an over thermometer, I was able to obtain a reading from the oven's metal parts. That suggested that the manufacturer's claims were false and using the standard settings has provided expected results. I have since purchased an oven thermometer just for this purpose.
The fryer's marking are extremely inaccurate and food was burning. Its marked setting of 150ºC when checked with this thermometer showed that its true range was between 165-173ºC, a sizeable error. A newly marked dial (with a dab of type corrector fluid) resolved that. So far, it has repaid its purchase price in properly cooked food.
Although the screen is not back-lit, it appears to be quite legible in most lighting conditions. I have used equivalent professional tools and this is not one, it is too plasticky for that. It is certainly a worthwhile purchase and can also be used to check the internal temperature of a cooked joint to ensure that it is cooked internally, or a loaf of bread as the shaping of the probe to a point makes that easy.
I cannot swear to its absolute accuracy; it claims to be within 1ºC or 2ºF but even if not, it does not detract from its usability in the home or perhaps in a small commercial kitchen. Considering a professional equivalent may cost the equivalent of 10 of these, it is a viable alternative. Do note that this is not intended for sugar cookery; you would need one with a temperature range of at least 250ºC/400ºF.
Recommended at the price.