We use it daily and it saves us a lot of time.
We have been using this cell counter for two years now, and have achieved very reproducible results. In our hands, the most critical step is to adjust the expected cell size in the protocol so that all cells are recognized and counted. The counting chambers are easy to use, and staining with for example Trypan Blue works very well, too. Overall, using this product has made our work a lot faster and easier.