Do I need to know Dungeon and Raid bosses well to be a decent Discipline Healer?

[TurboTrup]

I was thinking about picking either Disc Priest or Resto Shaman.
Disc Priest's healing is different, and most people pick RShamans anyway-- so that's what motivates me to pick Disc.
But I vaguely remember bosses.

Furthermore, I wanted to ask which of these two has a more varied and more unique ability/spell set? Or, at least, which one has a richer rotation during Dungeons/Raids?

[Mitzen]

Both have similar amount of spells in active use. Priest has more long CD's to use for own or raid's benefit.

It would be good to know general tactics of each boss. It's not rocket science, and you'll learn after a fight or two the general gist of who to heal and when and with what spells.