Well, I see that Mega-Altaria got the Minccino-Cinccino treatment. Disregarding Mega Altaria's potential impact on the competitive side of the game, it isn't making much of an impression to me aesthetically-speaking. It just looks uninspiring and bland. I guess simple tweaks could go a long way, but this one was just not executed to good effect. I would have liked if they kept the fluffiness level at a manageable state and gave it a more majestic look instead.
Mega-Lopunny...(looks like someone you'd see along the tamer parts of Red Light District) is certainly a spicy waifu-material, going deluxe dominatrix mode with that short "top" and skanky, "torn stockings". Kidding aside, for those very reasons, adding in the tied up bunny ears, these made Mega-Lopunny more fitting for its typing. That's not to say of my inclination to the design, which I find rather average at best.
Mega-Salamence's design piqued my interest but not in a good way....
Overall, I am left less than satisfied from a visual standpoint, but I am at least looking forward on how this Mega set will play out in the competitive scene, especially Mega-Altaria and Mega-Salamence.