This is definetly the most balanced AW yet, and if you have a friend the online play is awesome. But the random assignment for WiFi is so lame, random maps is ok, but no fog of war most of the time is really horrible. Couple that with always clear weather and alot of the fun is sucked out of random matches.
That and i hate when you get predeploy maps....
But other than that, i think its the best advance wars yet, if you love the multiplayer aspect which i do. However, if you just liked to play the comp on Dual strike, and power level your COs, beware that all of that is gone. Its much more focused now on competitive play. If you loved the old stuff, i'd say to wait it out until the next days of ruin, where they will bring in a more robust single player.
And tabithia is is no fun to play against when there are no airports or seaports... Man i wish they would let you pick the maps and conditions! That would make the game a perfect 10.
To the above comment, yeah its definitly shorter. I heard people complain about the difficulty making it longer, but i remember AW: DS being harder and longer. I expect a 3rd AW before the DS passes on, and I bet it'll have better single player, and more COs. The real question is, will it NOT have random wifi.