Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Worst Product I Ever Bought

I have owned a Roomba for several years, and have been very pleased with its performance, so I was very excited to purchase the Scooba. However, it has been the worst purchase that I ever made. The first one that I received would quit working every time it bumped into furniture or the wall. iRobt did send a replacement, but it only works about half of the time. The other half of the time, it does not vacuum up the dirty water, so it leaves the floor dirtier than before I "cleaned" it. I have contacted iRobot for help, but none of their suggestions have worked. Honestly, I would throw it in the trash if it did not cost so much.