I have 2 DA Lites & 2 DA Elites. I've been running DA, for 4-5 years. I've never owned an Apex, however, I would recommend Apex over DA. I've had a number of issues with SL1 modules, PH probes and accurate readings. In addition, Apex, has many more viable solutions (i.e. probes, controllable units for Ecotech, etc.). In addition, they are on the forefront of development.