I heard that you earn more experience when you’re not in a party and queue up with a bunch of random players. Is this true?
450% if you do a party with at least 1 of every single class tree (1 archer, 1 swordsman, 1 cleric and 1 mage)
and 600% xp if you use the LFG option at dungeon pole.
What if you use LFG at dungeon pole AND get one of every class tree? 600% + 450%? Just curious. 
No, only 600%
/20characters
The whole “bonus exp with 1 of every single class” is not true for our version (wether it’s bugged or intended).
To clarify, queueing will yield you roughly +50% exp as opposed to a pre-made party.