User blog comment:R. Lawton/How strong are some the GMG characters in comparison to Fairy Tail/@comment-2214433-20130911124138

That's subjective because it was said that during those 7 years that FT was gone, there was a period of peace. In that sense, while FT would always fight strong opponents and get stronger that way, there was nobody to challenge Sabertooth and co. during that time of peace. How strong would they be if they had to face enemies like Grimoire Heart or Oracion Seis is the question. They're not used to hardships, unlike FT, who, even if it's inferior to their enemy in raw magic, always finds a way to overcome it somehow.

Furthermore, I think that making match-ups of different time periods doesn't work, there are simply different circumstances for each group.