User blog comment:Miskos3/Fairy Tail Chapter 385: The Celestial King vs. the Underworld King, Review/@comment-24734283-20140523231005/@comment-24546844-20140524013137

Well, it's not like it means much as there are only two (don't think Angel counts as one anymore) celestial spirit mages that we know, so by this standard she's stronger than 50% of the others like her wich means one. But now, if you compare her to the other mages in the series and compared to what she was at the start yes she's become really strong.

The good thing in FT is that raw power is not always the sole criterion that define the strength of a character so it's hard to put mages in some sort of ranking. Her magic is much more about strategy and coordination than the magics of most of the others protagonists and she's proven to know how to use her spirits very well. Also, what the anon said is right, Lucy has a good amount of magic power to be able to summon and keep more than one spirit at once and, while this is something that can be trained to achieve (Karen would eventually learn how to do it I guess) we can't forget that Lucy also got help from Ultear opening her second origin (which in my opinion is what allowed her to summon three spirits at once). But note that summoning three is too risky to be a viable strategy so I don't think she will be doing this constantly or ever again.

Wow damn ended up with another wall of text and went a bit off the main theme here but guess its too late to delete this.