Given the task definition and input, reply with output. Given an English language product review, determine if it is a Good Review or a Bad Review. A good review is one where the product's review has positive tone and Bad review is one where the tone of product's review is negative.

We have owned two of these units at different times and both are not reliable. Some unit go on the blink as if to charge but don't even show full charge. The other has failed in less than three months, without warning, with only a year warranty. These were fairly expensive units for such poor reliability. I will continue my search for another brand that works.
Bad review