Vacuum Pool Cleaner

Above ground pool or in-ground pool.
If it is an above ground pool, go for the Hayward BUG.
In-ground pool cleaners, I would have to say Hayward or Kreepy .
The fewer working parts the better.
All of these robots can get stuck, in some pools.

Related posts:

1. Above ground pool or in-ground pool
2. Above ground automatic pool vacuum