Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Finicky and grossly inaccurate

This unit started out fine, apparently. However after 5 months of sparse use, it is now grossly inaccurate (about 40% higher on systolic readings, 15% higher on diastolic). My doctor says that the manual-inflate models are a much better bet. While Omron's customer service people admit that this unit is malfunctioning, they won't exchange it for a much-less-expensive model and referred me back to Amazon for help in getting a refund. They were quite argumentative on the phone about what they could and couldn't do.They did offer to replace the cuff, which they said was probably faulty, and only is "good for about a year and a half". That's astounding! Does that mean in order to maintain accuracy, a customer should replace the cuff every 18 months? I would NOT buy this unit again, and wish I'd purchased something simpler and probably more reliable in the first place.