Game looks gorgeous, how is the battle system? It it like Xenoverse or does it rely more on skillful playing rather than grinding?
The grinding means literally nothing except for unlocking Strikers (mobile suit partners that you summon, they do a quick attack, and then they vanish), titles, emblems, etc. Basically stuff that you show off for online matches
Anything you can do with a mobile suit at level 20 (the highest level) you can do with it at level 0.
It's the most competitive Gundam game out there. It's about skill. a 500 power mobile suit is theoretically the strongest thing available, but if you're skilled enough, you can easily beat a player using a 500 mobile suit like the Sazabi, using a piddly 200 power mobile suit, like the Hizack.
If you've never played a game in the Gundam versus series, it takes some getting used to. The combat system is unlike anything you've probably played before (although Xenoverse's battle system has similarities to this one) But once you've figured it out, you can easily adapt to any mobile suit out of the MASSIVE roster. Mastering a mobile suit takes skill, because different mobile suits have different strengths.
For example, my favorite one, the Mack Knife, is a close combat mobile suit. It has ranged weaponry, but if you're not trying to get up close and personal with your opponent, then you're not playing to the mobile suit's strengths.
Conversely, the Guntank is almost exclusively ranged. It only has one move where it can even do melee damage, and it's main close quarters attack is a gatling gun.
EDIT: Oh, one last thing. The game does have single player missions, although there is no story mode. So you can't use this game to learn the Gundam stories, really. Not that you need to know the stories to enjoy the game. It's fun enough to just play as giant robots fighting each other.
However, the multiplayer is where the most fun comes in. The single player's AI enemies can become predictable, but in multiplayer, you never know what you'll be up against, because everyone has their own strategy, and mobile suit of choice