Ulaire Nelya is the only Nazgul with a site 2 home.
Weatherhills is a
twilight site, whereas
Bree Streets is only a
twilight site. If you look at the
difference as the cost of Bill Ferny, then
Weatherhills is the superior site. Without Bill Ferny in play,
Bree Streets will play out better for the Shadow player.
Statistically, in a 60 card deck with Frodo and two starting companions, you are looking at a 56% chance of drawing Bill Ferny in your opening hand, presuming four copies in your deck. With a mulligan, those odds drop significantly to just over 32%.
Most people don't run four copies of Ferny and most people have a deck larger closer to 70 cards than 60, to put it in
perspective.
-wtk