I went through DUB PHL and LAX on the way to the PHX do. Couple of pros and cons.
Preclearance at DUB means arriving into PHL as a domestic passenger so no issue with the 2 hour connection. The A330 is a 1-2-1 configuration in J so no one sat next to you at the window. The 321T means you do have someone next to you, virtually guaranteed with the upgrade system on AA. I also love the old US Airways crews based in PHL and CLT.
The only downsides are really the lounge facilities in PHL, they are basic Admiral Clubs so no Flagship lounge, and there is only one A330 a day.