I've got the polaris 340..although it gets slammed on the forums it does do what it's advertised to do-

climbs the walls,steps and sucks up every thing that gets in it's way.

it was a throw in by the pool company however I think Id pay the 300.00 or so if i had to purchase it.

I'm sure there are way better options but I can't afford 500.00+ on anything that cleans the pool.

so this works for me!