It's nice in a tank that's cycling, but in a fully cycled, mature tank, it's not really necessary, as your ammonia levels should always be 0ppm. And as for the quality of the test, not sure if it would be compared to a dipstick test kit or not. If it is, then it could possibly be inaccurate. So I say it's not needed. Let's see what others say about it....
55G Filstar XP3 - 16" Fire Eel
75G Medium Planted - Filstar XP3 Low Light - Established Feb 2006