It has been about 5 years since I bought one of these units used, and it has been a real workhorse. I print about 30-50 labels a day, 5 days a week, and this little printer has performed flawlessly. It takes up very little space, and it's cheap to operate. I pay only for the labels (no ink). Be sure to shop around a lot for the labels, as there is a huge disparity in pricing, especially if you are going to buy them in case lots. Also, FedEx and UPS will provide you with free labels if you are using their shipping service.
It needs very little in the way of maintenance. Just blow it out once in a while with compressed air and gently wipe down the print head with 90% alcohol. FedEx provides special cleaning pads for this purpose, which you can run through the printer to clean the print head (free).