We have our own hand dug well, straight through the rock. No, we didn't dig it ourselves, but whoever did must have done something bad, because it's dug on a high spot of land. It's had its problems and needs to be cleaned out. We have a header tank in the attic, with a filter and UV, but recently I've been unable to drink the water. There is an electric pump to raise the water from the well to the tank in the attic, so no power = no water supply. Ours is one of only two private water supplies in the county, so inspections are not frequent.
Our neighbours have a similar system to the one you are looking at, a muddy, sloshy collection bit in the field next door, with cattle and sheep grazing around it. Some of the problems they have had have been refusal by the landowner to give them access to clear things up, totally blocked pipes full of frogs and toads and no access to clear them, falling out with the landowner big time, no control over chemicals sprayed around the hole, and their water supply drying up in summer. I don't know what their water pressure is like, but they are in a 2 storey house so should be a bit more forceful than ours. Problems of low pressure are the difficulty of finding a washing machine which can cope, piddly shower, no dishwasher, etc.
Before you buy, research putting in a deep bore, or getting mains connected. We have no chance of mains, and we don't need a deep bore, but our neighbours really could do with one. I did look into cost, but that was 20 years ago. You would also need to check on the permissions of sinking a deep bore, although the company doing the work may well deal with that.