I absolutely hate this game, so sad as jrpgs are ultra rare on pc and typically when they release one it is dire. What I cant stand is the combat, instead of controlling individuals you control lots of small groups and ahhhhhh it is just a freaking mess.
I personally think the combat is the best part of the game as it is something quite unique on it's own style. I mean yeah sure, you cannot control each character's actions and make them each use their own abilities, but I liek the fact that having huge group (Unions) battles makes for some very fun, long lasting games that really requires some strategy. It actually makes you think about how you want to attack and which would be the right move to go about.
And yes as mentioned above, you can purchase the game on retail disc for £9.99 if you look around. It will be connected with Steam anyways when you install it so it should be no problem.
As for the game itself, it is a hell of a lot better than the Xbox 360 version that is for sure, especially if you have a good PC system. There may be a few oddities in there, like texture loading when you first go into an area, but then that is in huge part due to the way the Unreal 3 Engine works (It will be the same for other games powered by this). There are some other tweaks and PC exclusive features like the Turbo Mode which makes the battles look hilariously fast, new skills and abilities, much harder monsters with higher health, and generally the overall performance of the game is better.
Yes it is no Final Fantasy, but if people can stop comparing it to that series and just because it's a Square-Enix made game that it has to be, then it can be enjoyable on it's own.
There really is no other alternatives for the PC, especially in the modern sense for JRPGs, unless you want to look at really older games like Breath of Fire IV, Grandia II and of course Final Fantasy VII & VIII. There are some good PC JRPG's developed by Falcom (Y's series), but they are pretty much Japanese only and with no intention of being released elsewhere in other languages, unless you want to dig deep and look for fan-made patches.