Any online RPG is, at launch, a work in progress, so the experiences of the first few days really give very little sense of the long-term potential of the game. I am writing this review after a week of (moderately intensive) play, and these views are just a first, shell-shocked insight for anyone thinking of devoting months of their life to this world.
The best thing about FFxiv is its crafting, which is incredibly deep, if rather frustrating. Even crafting a level 7 dagger requires the services of a blacksmith, a carpenter, an alchemist, a botanist and a miner; by the time the blacksmith assembles it, there will have been well over an hour of playing time devoted to manufacturing it. Usually in each low-level recipe there will be at least one item that can only be crafted by a higher skill level, usually in another profession; this stimulates trading between crafters, but pushes up costs, sometimes out of the range of the low-level character for whom the item is intended. Try the wrong recipe at too low a skill level and you will lost the materials. It's enough to make you tear your hair out, but is intriguingly complicated. Repairs, for example, can be conducted on items with the right crafting profession, the right materials and the right skill level. In theory you could make an in-game living simply by repairing other people's armour!
If it sounds as though all this crafting requires massive cooperation, perhaps through a guild of adventurers, then "yes and no". One character can, in theory, master all the classes and all the professions, which will suit a player who wants to concentrate on one character. Extra characters (unlike in World of Warcraft, but like FFxi) require additional subscriptions, so this will be a very expensive game for anyone hoping to spread out their gaming across several.
Cooperation is, however, a key aspect of any online game of this sort, and on the social side you can form guilds called "linkshells" so that you can ask questions, give advice or just chat. Many players currently use the translation system, meaning that conversations can be slightly garbled, and there is a problem with the number of words allowed for a line, and input lag, that means that the social side is not as enjoyable as one would hope. Given that most players are crafting for much of the time, the fact that you can't chat successfully while doing so is a major inconvenience.
The class system works very well, with even low-level characters being able to use the abilities of more than one class at any given time. Not all abilities can be used with all builds (some are specific to the weapon rather than the class) but it is very rewarding to find that your main combat spec has picked up a nice new ability from one of your minor specs. Changing class is as easy as equipping another weapon or - in the case of crafting or harvesting - another tool. Unfortunately you do seem to need to change the abilities on your hotbars, however, which makes things slightly unwieldy, and you cannot easily stop between fighting to mine an ore or chop down a tree, because you need to re-equip and change class.
The battle system in FFxiv is not entirely satisfactory. Although the game may improve in this area, targetting feels quite clumsy, and there is so much lag on battle animations that you feel oddly disconnected from things on-screen. Given that the game has a beat-'em-up logic (blocking, for example, is an active, not a passive skill) this lag is more than a minor inconvenience. Enemies feel few and far between but, worse, it is difficult to tell whether an enemy is an easy kill or impossibly hard: there is a system of colours that is meant to help you, but enemies that are supposed to be easy prey can be hard to kill, while enemies that show as very tough can be easily defeated if your character's physical level is higher than its current class level.
Quests (called "leves") are thin on the ground at present, with low-level characters required to do the same leve several times in order to raise their level. Oddly, you can only currently do eight of the main type of leve in 36 hours, together with eight of the crafting leves, so everyone has to go and collect their leves from the main city at the start of each period. Leves can be shared, making them easier and enabling characters to do more than their own eight. Moreover, behests, which take place on the hour, are a good way to try out parties, and present what can be quite simple combat challenges.
Sound is very good, both with regard to music and ambient sound effects. The graphics are (as ever with Square Enix) at least as good as they need to be and often better, but due to the graphical detail there is currently an absurd amount of draw-in delay: you can be walking through an empty market that after a minute suddenly fills up with ten npcs and sixty other player characters who were simply invisible previously. Perhaps once the servers are less busy, or after Square Enix increases its server resources, this will improve, but it is currently very poor indeed.
Another irritation is the economy. There is currently no auction house (and as far as I know no plans to introduce one), which means that players sell to one another either via their personal shop, or via their retainer, who keeps a permanent bazaar at the markets. The problem with this is that if you want to buy something you have to schlep from player to player inspecting them to see what they might be selling, although there is already a third-party bazaar finder online and the slack may be taken up by other websites and developers. An Economics student would probably have fun analysing it.
Overall, this is a game that requires a huge commitment in order to make progress, and it is currently not clear that the effort will be rewarded. Given that the first week of live play was marred by frequent service interruptions, a wise player might consider trying this out once the bugs have been ironed out and the server population stabilised.
I'll update if anything materially changes, and please feel free to add future changes in the comments to this review if you feel that it has become badly outdated.
[last revised 8 October 2010]