Yes okay, I know I'm a little late on the band-wagon, and haven't picked up Advance Wars: Days of Ruin yet, but money has been a problem, because I have to pay for hosting on all my sites, then pay to maintain them, so I haven't had a lot of money for new games, but despite all that I got Advance Wars: Days of Ruin when it was on sale, and I'd like to give my impressions about it so far.
Okay, first of all, the game looks great especially for being pretty much 2D and on the DS, and it really shows that they put a lot of work into the game. When you first start off, unlike the other games, you are introduced into a big story, and it really kind of make you think of how big the game is really going to be. You start off with a simple battle, that gets you used to how everything goes in the game (but I've played through and beaten all of the other ones, so I already know how it works), and it makes it really easy for anyone who hasn't already played it or any other games in the series to pick it up and play. After a couple missions in (I'm only at mission 10 right now), it's gets kind of hard, and you actually have to think of what your doing before you do it, and plan your moves out (especially in fog). Battles/Missions for me usually take from 20-40 minutes in the latter ones, and can be strenuous and tedious.
Wi-Fi is pretty good, and I've only played a couple of people, but there are definitely some kick-ass players out there, and even though you may lose a lot, it's still a lot more relaxing than the main game, and it's nice to take your mind off the main story for a while.
The really scary parts come around when you start clearing the extra missions. They're like the oldschool War Room maps, but more full of brutal rape.