Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good when it works, but!!!!!

This is a great machine when it is working, however, we have had a problem with reliability. Our first machine worked around a month, then stopped cold. It did display an error code which the support person we dealt with was unfamiliar with. They exchanged the unit and about 8 days later we received a new unit. The new unit never successfully fed a sheet of paper (jammed every time), and after the usual trouble shooting with technical support, this unit was also returned. 5 days later and now we have received a third unit which after 2 days appears to be working. The support was OK, with prompt swaps of non-working machines. After the second failed machine I put in for a refund as I was concerned about future reliability of a machine receiving critical faxes, but this was denied. Hope others have more luck with this unit.