Funny you should mention these two tires, as I'm presently riding on both.
When I went with carbon wheels I replaced the stock tires, which I didn't like, with a wider set (47mm) of Pathfinder Pros. I really like these tires on pavement and hardpack trails, but not so such on loose gravel.
A while back I got a serious punction (2" screw) through the tread on my rear tire and it chewed a big enough hole to destroy the tire. I'd read a couple of really good reviews on the Terreno Dry tire, so I decided to replace the destroyed tire with the Terrreno.
I bought another Terreno for the front, but there's a lot of life still left in the Pathfinders, so I haven't replaced it yet.
My 'seat-of-the'pants' comparison of the two tires is the Pathfinders are faster on pavement and the Terrenos are a bit better in the looser stuff.