Piper's is satisfactory in some ways and excellent in others.
For instance, if your thing is waking up at 8am on a Saturday to stand around a bar and watch Premiership matches until 2pm, you probably already know, there's no better place to do so in Pittsburgh.
If you're at home on the South Side, you'll enjoy the vibe here. Personally, for a British-style pub, I'd like the entire place to have as much character as its entryway. Throw in some drab green carpet and trough-style urinals if that's what it takes.
The pub fare here is good as well. The portions they dole out are substantial which is great if your hungry/hungover -- as many tend to be -- but overwhelming and potentially disastrous if you're of the mind to moderate your consumption. I've eaten here a handful of times, but nothing has stuck out to me enough to comment on specifically.