My experience is that it works well in general, but some landowners are better than others, and some highway authorities (which enforce the laws) are more zealous than others. Most of the issues I see around me is farmers allowing crops to grow through low use footpaths such that they become impassable.

The other tricky bit of PRoWs is that any path used by the public for 20 years continuously, without force, secrecy, or the landowner's permission, is legally presumed to be a public right of way, even if it isn't shown on the definitive map kept by the local authority. That can lead to legal fights e.g. [1] and [2]. There are also 'permissive footpaths' where landowners have agreed to allow the public to pass, but not become a PRoW. There are also s106 agreements (planning obligations) where developers must allow the public to use land as a footpath. The Thames Path has a mix of these.

In Scotland, there is a more general 'right to roam' which allows anybody to access most land (excepting buildings and their curtilages, military sites, and other obvious exceptions), but there are affirmative duties to maintain PRoWs that don't apply to open access land making them still relevant. England and Wales have some limited open access land as well, but much much less of it. NI has no open access land and (subjectively) fewer public footpaths.

[1] https://www.ramblers.org.uk/news/ramblers-win-court-appeal-1... [2] https://www.ube.ac.uk/whats-happening/articles/pippa-middlet...