We've been using a Dolphin DX4 with our pool since it was built 4 years ago. Overall, the robot is good (once I learned, after 3 failed power supplies, that the power supply must be covered) but it spends a lot of time "spinning" on top of the main drains. Sometimes it will just spin around one of the drains for 5 minutes or more before "freeing itself" and moving on. This model has a single drive track that spans the entire width of the robot. The problem is that, because it gets "caught" on the main drains so often, it sometimes doesn't clean the whole pool.
Is there a another robot out there (either Nautilus brand or something else) that doesn't have this problem? I don't know, for example, if the Dolphin cleaners that have a "split track" might be better suited for us?