Which caster to start with?

[Swish]

It depends on the synergy of the group, if the cleric is struggling with a ranger/bard tank, a bad tank, or something... that's probably the best avenue to prevent frequent mana breaks, patch heal/cancel magic costs next to nothing, you're only spending the mana on twitching and the occasional lifetap.

I agree though ideally I mostly preferred/enjoyed charming a pet, tooling it up, hasting it (if no better haste was available) and really motoring the group's dps output, with screaming terror on a hotkey for the inevitable break ^^