The places you mentioned would all fall under "cheaper because they're a bit ropey", but all do have a lot of heart and community spirit. I wouldn't voluntarily live in any of those places, though. The places you mention all also have fairly rubbish transport links.
Most of Monmouthshire is lovely, although there are small pockets of "ropey". There's some excellent parts of Newport, Swansea and Cardiff. As people have said, furrhest east (Monmouthshire - largely affluent and good transport links) and furthest west (beautiful) tend to be "naicer". I'd also add in that, on rhe whole, the further north from the M4, the less "naice", although there are significant exceptions, and it doesn't follow that the further south you are the nicer it is.
Maybe those of us who live here could suggest places if you tell us what's important to you.... transport links, public transport, schools (public/private), closeness to amenities, city, town, village, rural, availability of cultural events, etc?