Match the cleaner to your pool's surface and shape first, then decide whether you need waterline and wall cleaning or just the floor. Cordless models are far easier to live with, but check runtime against your pool's size and how heavy the unit is to lift out when it is full of water and debris.
Floor only, or floor, walls and waterline
Floor-only cleaners are cheaper and adequate if your main problem is sediment. Waterline cleaning matters most where sun cream, pollen and oils leave a tide mark, which is the part guests notice. Climbing walls reliably is harder than it sounds and depends on the surface: tile, vinyl liner, painted concrete and pebble finishes all behave differently, so check your surface is listed.
Runtime and pool size have to match
Cordless cleaners are limited by battery, so a quoted runtime needs to cover your whole pool with margin. A unit that covers 80% of a large pool per cycle is a unit you run twice. Corded models avoid the limit but bring cable management and a tangle risk in irregular pools.
Retrieval is the daily reality
You will lift this out of the water regularly. Weight when waterlogged, whether it parks itself at the waterline, and how easy the filter basket is to empty and rinse matter more day to day than any cleaning specification. Ask about the filter's fineness too, if pollen rather than leaves is your problem.
Questions people ask
Cordless or corded?
Cordless for convenience and irregular pools; corded if your pool is large enough that battery runtime would force multiple cycles. Cordless has become the default for domestic pools.
Will it replace manual cleaning?
It replaces routine vacuuming. You will still brush occasionally, manage chemistry, and clean the filter basket after most cycles.
Does pool surface really matter?
Yes, particularly for wall climbing. Check the manufacturer lists your surface — a cleaner that climbs tile confidently may slide on a vinyl liner.