Jokes aside gaining levels is mostly reasonable until you get to my level (I'm the highest member of the guild at 27 since I've been playing way before anyone here brought it up) and grinding is hell here. But the people I've helped like Hazama and people level up at a more decent pace it seems. Should be noted gaining levels in necessary but not really the focus. Instead you should mostly be focusing on grinding Expertise, which basically means you'll be using skills to learn more of the same type.
For example, Casting Dia over and over and over again to learn things like Patra, Media, Diarama, Recarm, etc