The iPhone version of Final Fantasy Tactics is a port of a port, an enhanced remake of a game that was originally released more than a decade ago. It's a game that costs $16—roughly 16 times the price of most iOS games. It's old, expensive, and you can find it elsewhere for cheaper. Then again, it's also one of the best strategy RPGs of all time, playable on your phone. So maybe it's worth it.
This isn't actually a port of the original; it's the PSP remake, subtitled The War of the Lions, that was released a few years back. This means that it has the beautiful, animated cut-scenes from that version, as well as new content like additional classes to unlock. So it's a pretty meaty package, with easily dozens of hours worth of content.