Well, I had an OK experience with Transpac. However, I was really happy when I walked out the door for the last time. You'll fly a lot, and I mean a LOT. Expect 10 hour duty days and at the end of the day you'll be tired. Go home, sleep, do it again 5 days a week. They tout a hefty safety culture but it is a bunch of BS. Just don't fly if you're not comfortable or feel it's safe.
If you're going to go there, CYA (cover your ass). Any mix up with students/paperwork/FAA or any other issue you'll be thrown under the bus. Overall an OK place, but I didn't really care for the way things are run in middle management. They're too reactive and short term thinking instead of being proactive. I couldn't really tell you about upper management, but I got the impression that the decisions are really just based on counting beans.
Keep your head on a swivel and don't get complacent in the PHX practice areas and airspace. Lots of Transpac instructors have been violated for airspace.
P.S. You'll learn to hate "The Stack" head on a swivel.