Landis by a mile.
The meck and Wolf books are similiar IMO, and neither come close to what Dwight was able to put together. Meck's book really gets bogged down by repetitive, poorly written fishing stories. Also, ome of the maps are incorrect. Wolf's book suffers from similiar problems. Also, both try to talk as experts on every stream they describe when it is evident they aren't.
On the other hand, Landis's Trout Streams of Pennsylvania really delivers when it comes to finding the info you need to actually get to a stream and fish it. Good maps, plenty of stream descriptions for all parts of the state, practical hatch information, and no bull. It is everything the other two books aren't.
Kev
P.s. A delorme PA atlas and gazetteer is also incredibly useful. paired with a copy of TSofPA, you will be busy for years exploring new places.