[Qbot2640]

We had some trouble with a very similar encoder last year because our application made it difficult to get the magnet lined-up perfectly with the sensor on the encoder. If it is out of alignment, it will give bad values. If your application is similar, you may wish to use a potentiometer instead. The number of turns it would have to make could be a deciding factor, as continuous rotation potentiometers are expensive. Wiring and programming* are the same, so you can swap it out if you have a problem. We did.
*you will probably need to tweak the values, depending on the potentiometer you choose.