Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: amazing little vacuum

Now here's a product, the I Robot Roomba, that simply exceeds expectations, it's amazing the amount of dirt this little vacuum robot picks up. Weakness appears to be the battery. The first Roomba sent to me had a battery life of less than 15 minutes, the 2nd unit sent is better and the battery life seems to improve every time I charge it, running a little longer each time and now up to 1 hour and 15 mnutes per charge, but not the 2 hours claimed by the manufacturer.