Was visiting Pittsburgh a few weeks ago and happened upon Lidia's mostly by accident.
A happy accident, for sure.
Lidia's has a nice selection of various pastas but their main attraction appears to be the Pasta Trio, where each day three different types of pastas are selected, each type having a waiter/waitress assigned to walking around and making sure you've got as much of it as you like, sort of the same thing gauchos do in Brazilian steakhouses.
My friends got the Trio and were quite happy with it. I went safe with the lasagna, which was perfectly cheesy and saucy.
Dessert had a name I can't remember, but it was a kind of chocolate/caramel ice cream with a toasted marshmellow coating around it and little bits of toffee. I shouldn't have eaten it all but my arm and my mouth conspired against me. Jerks.
A nice ambiance and friendly waitstaff certainly don't hurt. Next time I'm in Pittsburgh, I think I'll be seeing Lidia again, and I don't care who knows!