120 hours spent on one job does not teach you how to play or gain you any further skill than a few solid evenings polishing off your last ten ranks. I much prefer to have my classes brought up to the early 40 range (maybe peppered with a handful of leves here and there to gain guild marks for additional abilities and getting the basics down), and then taking a full party out to a stronghold and finishing things off while spiritbinding gear. It's in those last several ranks that you actually learn how your job works, since you're actually filling out your ability bars anyway. Weeks upon weeks of jamming the same 3 abilities over and over because that's all you can afford to put in your bar is neither engaging nor developmental to your character.