I am currently running both in my tank, and have been for almost two years. Positives of the WAVS are they are integrated into the Apex and they are directional. Negatives are they need to be cleaned way more often than any other pump I have ran.....they lose power quickly if not kept clean. Positives of the MP40s are them being cordless and they are easy to keep clean (using an extra wetside they can just be swapped). Negatives are they are not directional and their magnets can sometimes be finicky. The WAVS seem to provide a bit more water movement but they are both pretty strong.