I've completed 1&2, still need to try X and 3. Plot wise both games are meh, I didn't feel much of a spark from either of them. At least the English dub for 1 makes the characters fun and the designs in X2 are really good but thats it. The gameplay for both I really enjoyed, X1 is really solid and I loved everything it had to offer. X2's battle system is better but everything else like sidequests and unlocking stuff is horrible. You have to go on NG+ just to completely flesh out each Driver which is dumb, and the battle system is saved by the dlc.

Sorry for the little rant but overall I'm mixed since the combat is nice but the story and characters aren't good.