Targhee is great in the respect that there it is so low key. I've skiied there on a 12+ day and not waited in a single line. You can find powder days after a storm. Most of the mountain is pretty low angle but there are some short steep shots that can be really good(The north facing Sacajawea*sp lines and 'East Woods' are great).
Jackson is the exact opposite. On a powder day, you better be waiting in line before 9 if you want to get untracked turns. The best areas get crewed up before 11am. On the other hand, the entire mountain is steep and stacked with amazing terrain. You can find sick stuff pretty much anywhere on the mountain so its not really worth me listing stuff, just get out and explore (Cirque, Alta shoots, Saratoga are good places to start). Definitely hike the head wall bench a couple (take the Tensleep traverse) times and check out Casper Bowl and the Craigs.
If you have solid back-country experience (+equipment) the side country is amazing. Its also extremely easy to fuck yourself if you don't know where your going.
Have out here. Don't kill yourself