I got Valkyria Chronicles as a gift this holiday season, and have very much been enjoying it. I really liked the Advance Wars series, and as I've said to others, Valkyria Chronicles is a little like a third-person Advance Wars RPG. Add into that a great art style and a very PG game experience, and you get a very accessible strategy game.
From a gameplay standpoint, Valkyria Chronicles is a turn-based action game. You choose a squad of teammates from a pool of up to twenty characters at a time that consist of five different classes -- Scout (a quick recon unit), Shocktrooper (a machine-gun soldier), Lancer (with bazooka anti-vehicle Lance weapon), Sniper (self-explanatory), and Engineer (the repair and ammo guy). Each plays a role and each has its strengths. In an encounter, it makes sense to bring some of each class, because you're going to see lots of different enemies at any one time, requiring you to have adequate responses. It is possible to both retreat your units and call up reserves should any of your squad fall down on the job.
Outside of the core gamplay are a host of RPG elements that add depth and complexity. You can mix and match the members of your team anytime outside of a mission. Different characters have different abilities, dependant on their background. For example, one of the main story characters was studying to be a biologist, and is thus at home in a natural terrain, gaining a status boost from being in a forest. Similar bonuses -- and negatives -- exist for other characters for other terrains. Additionally, some characters have friendships with other characters, giving them bonuses for working with one another, making you want to obtain and locate certain characters closer to one another within a mission.
Of course it wouldn't be a RPG without levels and items. Valkyria Chronicles has mechnics for both. As part of completing missions and skirmishs you gain experience and credits. You can spend experience on the training field levelling up a certain class of character (each character of that class levels simultaneously). Levelling up adds ability scores as well as the potential for other bonus characteristics. Similarly, you can spend credits on researching new armor and weaponry. These may take the form of weapons with greater accuracy, damage, or status-dealing effects. You can choose where to invest your credits, and how the research tree is managed.
The story in the game is adequate. The characters are likeable if a bit predictable and cliched, but at least you know the roles that each plays. But it's an appropriate message for this game about characters, in that the story illustrates the human cost of war, and the loss of home and friends as a result of a greater, and frequently misunderstood, conflict.
The game has just been a ton of fun, and proves to me again that the PS3 has been a place for incredible games this year. Starting with Gran Turismo 5 Prologue, moving on to Metal Gear Solid 4, LittleBigPlanet, and now Valkyria Chronicles, the PS3 has finally established a great stable of exclusive games. If you enjoy strategy games and have a PS3, you have to look at Valkyria Chronicles.