Upon leaving a town you'll enter a field. Fields and dungeons differ from towns in but two things:
1. In towns, you'll only see Vaan's character model. Maybe at some later point in the game you'll see another character take his place, but for the 25+ hours I've had the chance to play it, it's all Vaan. He's the main character, so you're stuck with him,

. On the other hand, you'll see your three active party members and additional guest member when in fields or dungeons.
2. Enemies (duh). Now, obviously, to fight enemies you need your weapons, which are also displayed, and yes, every weapon and shield has a different 3-D model. Armor and accessories don't appear, though.
Fields are aurally breathtaking, to the point where you'll wonder if it's really your PS2 producing these visuals. They're also easy to navigate, and you have a nice little map in case you get lost. For the most part, enemies are relatively easy to avoid in fields; although, since there's really very little hassle in killing them and earning experience points, you might not want to unless you're in a pinch.
There are, however, very powerful enemies roaming the fields right from the start. The huge T-rex in the first field comes to mind. These enemies won't attack you unless *you* pick a fight with them, but you had better not. Still, even if you do and they start wiping out your party members with a single blow, you can usually run away successfully and escape to the nearest save point.
Now for my beef with these fields: they're simply *way* too big. I'm not talking Willy the whale big, I'm talking *Titanic* big. As in *long*. As in, you might spend a good hour traversing them, and more, in some cases. Of course, this is considering the time spent killing enemies, but even so...
This would not be bad if crossing them were particularly entertaining, but, eventually, I found myself getting bored, and the reason is simple: no worthwhile treasure chests. Honestly, in 20 plus hours I've found like FIVE treasure chests of any actual relevance. The rest are all "potions", "phoenix downs" and pocket change. You'll eventually find gambits in there, too, but none you can't actually buy for 50 Gil a piece in the local gambit shop.
Also, all treasure chests are neatly tucked away in corners. All you have to do to is visit the corners on the field map you're on and
voila! you have... 3 more potions with you.
Joy.
Dungeons are much more entertaining, as they feature simple puzzles and bosses, but there's still a noticeable lack of treasure chests.
It all comes down to this: unlike it's predecessors, Final Fantasy XII is, in essence, a
dungeon crawl. It's Vagrant Story 2, pure and simple. The only problem is that Vagrant Story always had interesting treasure to find, and you could forge your own weapons with these items, while in Final Fantasy XII you...
can't.
There is another facet to dungeon crawlers, besides treasure hunting: stat building, i.e., leveling up your characters. Therein lies another problem I have with FFXII, which I discuss in the next section (when I put it up).