I'm a huge fan of Legendary (got most of the expansions) and Lotr LCG.
I won't say this is a better game, but it is for me at the same level of fun.
Why? Because in my eyes these tree are totally different and that's what it makes so much fun!
Because of the Marvel theme, the way you have so, so, so much choice (if you have many expansions) of hero's and enemy's. Because the schemes are so awesome and because the deck building part itself is so focust on the building part. You really need to build!
Again, the theme. That on itself makes this game unique. But the way you are really do a quest, your more in a story then Legendary, that is what makes this game so good and so different. The deckbuilding part is in my opinion a lesser part of them game then Legendary. But the depth of this game is mindblowingly (is that a word?!) good!
The point i wanted to make is this. Lots of ppl say that there are to many coop deckbuilders.. But wait, how many dice, worker placement, builder etc. games are there?! For me it is not a bad thing there are many. Because there are so many, people need to get creative, and that is what Aeon's End does.
The amount of work they put into this bosses is huge! Every single boss is different. More different then with the other two games. The small extra things like the charges, the breaches and the turn order cards are so smooth. They are not gimmicks, they are fit right in this game.
Then the part that you can't shuffle your deck is also so cool.
The part that you have life, but you are defending Gravehold, so even if you lost all of your life, the game go's on...
I think the good thing is that this is not one of those games that just looks cool and does the trick we have seen before again. No, this game plays with the genre. Also this game has a lot of potential for the future. I can see that with this foundation you can do so much good.
For now, there is enough to play with. The fun thing is, that i played some Nemesis over and over again. And every time i played, the session went totally different. Still, with a good strategy you can win this game.