Anything in Plate is grind friendly. anything in cloth will have problems with more than one mob. Rangers (once past the lvl 1-15 hell time) can kill most things without taking dammage and hardly use mana, so they grind non-stop, but it is a tricky grind full of diffrent kiting tricks. Preist and chanters can go non stop if you focus on alchemy a bit for free pots. but i find that when tring to catch up, once you hit BC and beyond, it is a lot easier to be in demand (Cleric or Tank). Due to the lare ammount of grouping needed.

Last thing you want to have is to be tired of sitting on your main spamming for groups, just to roll over to your alt to sit arround, spamming for groups.