The Southern Uplands are very much less dramatic then their northern counterparts. They are rounder, grassier and not to mention generally not as high
But ... for me they have a charm all of their own. I love walking that area.
Since they are less traveled by people, they tend not to haver any paths. That's a huge plus for me, it adds to the sense of wilderness and exploration. The hills being rounder and generally having less bits to fall off, makes them perfect for making your own routes and generally using them to school navigation skills.
But we all like different things. Each to their own, etc. There are plenty of hills out there to enjoy