Instruct: Classify a given Amazon review as either positive or negative.
Query: Very good humidifier, not the longest run time

The unit works well and seems sturdy enough. I gave it 4 stars rather than 5 because of two, relatively minor, gripes:1. The run time on the highest settings is less than 24 hours. To my mind, one of the conveniences I look for in a humidifier is having water tanks that are sufficiently large to avoid daily filling. For a unit this big, the tanks don't hold enough to last a full day on the max settings.2. The following complaint is, I admit, so small I'm almost embarrassed to list it: The handle on the top of each water tank makes it impossible to walk away from the tank while it's in the sink filling with tap water. If you don't stand there and manually hold it upright, the tank will simply fall over. It's not a reason to avoid this product, but it would have been a nice feature.