I bought it and it's not bad. If I were to run a full-scale incursion campaign it would definitely be worth it, even if just for having a wide range of githyanki stats already prepared.
Frankly, I wish I could buy all Dungeon adventures this way. They're far more useful to me as I can copy out the stats from Acrobat and run them from my laptop. Plus I can extract the art to show the players again from my laptop.
Cheers
D