Generally speaking…
VDH and Prot Pally are the easiest.
Guardian is boring, but easy.
BRM? I honestly forget it exists.
Prot Warriors have annoyingly long CD’s.
Blood DK is the hardest, but probably the most fulfilling.
I prefer the BDK over my VDH, but the skill floor and ceiling are noticably drastically different. BDK having a higher floor and ceiling.