Since I am the author of XP per level requirement I obviously track some players regularly in order to get the data. I would like to thank @uclapack for providing the screenshots every time she levels up. Btw congrats for reaching level 78 yesterday!
Top level afaik is Camoes of POR PORTUGAL (82), then MANU of Oceano Pacífico (81). There is a bunch of other players I got my eye on but speaking about who levels up fastest at the moment of the players I track and who are all level 75+ I gotta say it is Ninjamoe of Seven Days Fermented who is not only the fastest to got the missions done but he also leveled up 5 times in the last 40 days. He is now up to level 75.
Keep your eye also on Elektrik of Agressive, Jacobus of Seven Days Departed and Bad Triceratop from Ritual. I am a big fan of all these players (gotta also mention Zero - lvl72 currently)! Keep up the good work!
I am myself on level 61 and fighting with none of The Jerk Store also level 61 for the top spot in the Czech Republic.
If anybody knows for which alliance Alex Forquet is playing, please let me know here.