User blog comment:IamJakuhoRaikoben/Chapter 440: God Serena, Review./@comment-26389992-20150615123219/@comment-25111584-20150616210646

Laxus only took some of the Magical Barrier Particles from Tempester and completely collapsed. Juvia took all of Keith's and was just out for the count. You can see her in much better condition than Laxus ever was when she looks in wonder at Igneel's appearance.

A Mira whose Demon Factor had been refreshed was having trouble defeating Seilah even when the latter was not able to use her main weapon. Erza, after her battle with Minerva, was able to defeat Kyouka who absorbed Seilah's strength and then got empowered by the trigger.

We still know that Laxus is tonnes more durable than Juvia. We still know that Mira and Erza are quite equal, even though the above example shows that Erza is miles ahead of Mira.

Conclusion: Feats don't mean much in FT. Mashima has serious problems with consistency.