The statement that MONKS have a 20% penalty is perfectly correct - especially given the context of correcting someone specifically referencing the class as having no penalty. Yes, Iksar Monks have more of one, but that's because of their racial penalty.
With regards to saying that an Iksar Monk is worse than other other class to have in a group... that's only if you're grouping purely based on level. Ideally, you want to group based on total character xp which ends up with everyone getting the same xp per kill even if there's a multiple level gap between characters.
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