I have played X-Wing almost exclusively for several years and own over a hundred ships, so I think I have a pretty good grasp of the game. Mind; I quit when 2.0 was forced upon us, so I can't speak for the newer iteration(s); I'm strictly a 1.0 guy...
And when it came out, I was pretty stoked about Legion. Finally a contemporary, easy to play, Star Wars miniatures game. The only downside for me was the fact that I had been stockpiling WotC Star Wars minis for years, and the Legion scale was just way too big to match up with them. I chose to go ahead and sell off the Legion minis and then acquire the cards and tokens for my units as I went on.
But the expected (by me) flooding of the market of the cards and tokens, as people only wanted the minis did not happen, and I had to buy several expansions and then flog the minis, as there were barely any offerings of the gaming aids without the minis. This put a dampener on my Legion ambitions, and I ended up playing only a handful of games.
This was in part because of my regular opponent being heavily invested in Imperial Assault, having painted each and every mini in that game. And because that game too was in yet another scale, he didn't want to paint up the same minis in a slightly different scale yet again. Which, honestly, I get.
So the games I did play were really enjoyable, but obviously I'm not the Legion veteran as I am an X-Wing one.
If you play X-Wing, the gaming aids in Legion should be familiar, with a few caveats. There are unit cards and there are equipment cards that you can add to the units; same as in X-Wing. But in X-Wing, there is a card for every mini/ship on the table, while in Legion there is one card for each unit, and a unit can be as large as 7 miniatures.
There are the tokens, which are, again, familiar to X-Wing players. Some go on the cards, others go with the ships; you know the drill. These tokes represent status effects, wounds, etc. Also; there are proprietary 8-sided dice with symbols, just as in X-Wing. Symbols are different of course.
Then there is movement. Here there is a slight variantion compared to X-Wing and perhaps Armada might be a closer match. In X-Wing you have separate templates for each movement (straights, banks and turns, in several lengths) and you assign them through a ship dial. In Legion however, you have straight templates for slower infantry moves, but also templates that articulate at certain points, so moves can be adjusted. To the terrain for example. This is very reminiscent of the movement templates in Armada, which use the same articulation.
In play, the game is obviously different, if alone because of terrain features and different types of unit. Some are single figures, such as Darth Vader or Luke, but others are full units of 7 individual miniatures, to which minis with special weapons can be added. The game is more about traditional positioning and taking cover than it is about manouevering; units can opt not to move for instance, something that is (usually) not an option in X-Wing.
Add to this the introduction of vehicles such as walkers and speeders and you get a completely different dynamic, even though the gaming aids are of the same high standard as in X-Wing, and should look and feel familiar to any X-Wing player.
Just don't expect a completely comparable experience, because under the hood, the games are necessarily different.
Would I reccommend Legion? I think I would as an introductory game for those starting out in tabletop wargames, especially when coming from a boardgaming background (and X-Wing!). However, it can get expensive quick if you want to expand, and the chosen scale and required unit cards basically restricts one to this single game and expanding into other miniature games will be a big step still. 3D-printing is a great help here, but then you'll also have to create templates for unit cards etc, in Illustrator or Photoshop for instance, if you want to keep with the game's high level of aesthetics.
In conclusion; it's a nice and easy to learn game that has its own ecosystem and cannot be easily expanded upon outside of it without a lot of work/time/expenses. So yeah; a lot like X-Wing actually...