the challenges are actually very forgiving in this game compared to cod.. i keep seeing alot of 10,000 to 14,000xp bonuses in my play through.. and for every time you go through generations, xp is doubled so going from 1 to 50 gets shorter than first play through
there is a maxed of 10 Generation levels...... this dude maxed out in 4 days
Titanfall Player Hits Max Level in Under Four Days - IGN