The only game from the Wild Arms series that I played was the first one, it was alright.

 The story in Wild Arms 4 is horrible, it seems like it was written by a child and is basically the oposite of a regular Wild Arms game and not in a good way. The chacracters were bland and 2 dimensional as well which didnt help very much.

The battle system in it is the one saving grace being fun and kind of unique, but the problem is that the battle systems returns in Wild Arms 5 and is improved making the only good quality of Wild Arms 4 a moot point.

I would reccomend getting Wild arms 5 and especially Wild Arms 2 if you can somehow get a hold of it.

As for the situation with Wild Arms Alter Code F and the original i'd say only get Alter Code F if you don't have an online enabled PS3 because if you do have one then you could download the original wild arms for only $4.99 instead of the $25+ that you could normally find Alter Code F for.

you forgot suikoden is great too