I think that you might mean Rehoboth Place? If so, then it seems a really nice little street. And beside one of my favourite D8 pubs, Lowe's.
As has been said here before, there are some dodgy patches in the city centre, but there are far more decent places, and that as long as you keep your eyes open you should have a great experience.
When people refer to Dolphin's Barn they generally mean the Dolphin's Barn flats - which have a lovely location looking onto the canal, but have been the epicentre of much social deprivation. But that's not to say that the entire area suffers from similar problems.
If you're interested in a nice period house in a central location, and don't mind living in a socially mixed area, then go for it.