I for one don't care for the new app at all, and many others share my view for several reasons:
1) childish animations
2) inability to create QA setups
3) inability to chat with friends
4) No personal achievements
Take a look at this topic, quite a landslide vote to say the least, the only person voting in favor of the "new app" was its creator
It's getting a bit off track to discuss the new app, but although Fairway is correct in 2), 3), & 4) (and 1? ), the new app does have some distinct advantages over the old app (which is no longer availble) and even the website version that one can play on his phone with the Puffin browser. The shape of a phone screen lends itself well to the taller shaped pieces and, although they take some getting used to, I'm comfortable playing on either venue at this time. Often I feel the Puffin version is a bit glitchy so I stick with the new app, but sometimes you just have to have the good old website game again. Puffin saves the day then!
Anyway, on the new app the graveyards are the biggest thing. You couldn't see them on the old app and you can't see them very well on Puffin, at least without getting out of theatre mode, which a somewhat dangerous thing to do during a game. In the new app the graveyards are huge and easily and quickly readable. But be careful about where you are playing! In the website game the graveyards have yours on the right and opponent's on the left. In the new app this is reversed so that yours are on the left and the opponent's on the right. You just have to be careful about where you're playing.
I think the popularity of stratego is not tremendously affected by the new app, but it is just another of those many things that are odd. You can go to stratego.com and play one game; then play on the app and get a completely different looking game.