@kristiedegaris Yes, Welsh walls tend to be very neat, aided by the properties of slate. Sandstone or limestone walls are often more irregular and there's more variety in the stone itself...love them all.
@Judeet99 I grew up in Caithness where it's all flagstone, a similar look to slate. We build a lot with rough fieldstone in Perthshire, and I love a fieldstone wall.
@kristiedegaris It's mostly limestone here in Derbyshire although there are different types. We do have some lovely sandstones too.