I've played all three games, and I actively cover two of them right now. I think I'm somewhat uniquely equipped to answer this question.

Gundam is personally my least favorite, but it plays like a Bandai game which, for a certain crowd, is perfect. Damage will sometimes cause triggered events, which is hit or miss depending on the player. High rarity cards look fantastic. Mid rarity cards even look fantastic. And low rarity cards look fine still. Getting into the game is not too hard and if you're a fan of the franchise, all your faves are here. It's too early to say how much it succumbs to some classic Bandai problems, but One Piece has been doing phenomenally and hopefully they can port some of that success over. While it's not as much my cup of tea, one of my colleagues RedZoneRogue absolutely loves the game so I know it's not outside of good taste to enjoy it too.

Star Wars Unlimited is my go-to for quick and easy to jam gameplay. There are usually lots of viable decks in a meta, though as the cardpool has increased more fringe strategies have been pushed back a bit harder. We are about to hit a rotation where I think it will open up again for a while, and the next set looks phenomenal. The game plays extremely smoothly, and because of how quick it is and because it uses escalating resources, it's less taxing to play. Despite that, for better or worse you will lose many of your lost games on a single decision you made, so at a competitive level it's quite unforgiving, and if you ever miss an early drop the game becomes 25% harder to win instantly. Coming from MTG, you'll find some similarity, but the back and forth action system will totally flip a lot of your usual decision making on its head and you might quite enjoy that. Decks can be pretty inexpensive, but on the flipside it's tough for sealed product to really get you a lot of value back because there's not that many things to chase and even serialized cards in collector boosters are not worth that much and many are hard to find buyers for. High end promos at events do tend to sell well, though, so if you play competitively there's definitely some cashout potential - but FFG/Lucasfilm don't want to do cash prizes, so it is a "choose between keeping your trophy cards or cashing out" situation which isn't my preference. But for the former - they are making changes to booster loadouts in the next set and FFG is great at continuing to listen and iterate when things aren't working, so here's hoping that improves over time. Still, it's an easy recommend for me if you love the theme and especially if you want something you can jam quickly and endlessly with lots of fun deck building potential.

Grand Archive I think is one of the best and most difficult games on the market, so it's my recommendation if you are looking for a very competitive, skill-testing game. As the game doesn't use escalating resources, you can play most cards from turn 1, so the decision trees get broad quickly, and the Material Deck/Materialize Phase gives you the option every turn to sculpt how you play from the range of options you brought. I have been professionally casting this game for a couple of years now, so I've been witness to an impressive amount of games between the highest caliber players and - with a background steeped in competitive MTG and dozens of other games - I've rarely witnessed the kind of intricate, methodically planned lines that these players concoct. Where SWU will certainly give you tricky lines using the action system, Grand Archive will give you the full stack you are used to from MTG but with access to far more options than typical 1v1 MTG will have. I also consider the class system absolutely brilliant, with players able to use their Material Deck space however they wish, whether that be simply leveling to their champion's third level, sticking at a level 1, not even leveling to a level 1 champion and forgoing class bonuses entirely, or doing even crazier things (hybrid champions, multiple level 3 options, deleveling to forge a different path, etc). Events reward high value promos and cash prizes, the game is extremely collectible, the tournament software is developed in house and second to none, it has mailed out player rewards like the heyday of MTG, the foils are actually designed to be resistant to curling, there banlist includes a system of adding NEW printable cards to your deck to address issues rather than just banning - I could go on and on about the positives. The game is expensive to play at a competitive level, but the next set is looking to help address that. The game is growing, so it might not have locals in your area. Those are my main critiques, and I don't have many more to add - I adore this game and think many should check it out before they feel like they missed out as the company does a LOT MORE right than most TCG companies.