Assassins are awesome to play. They have the ability to teleport via "shadow arts" which can put the jump on the enemy. The shadow arts also come in handy with other classes like giving monks a nice way of escaping and teleporting to an ally or a giving an elementalist the ability to teleport into a group, spam aoe spells, a teleport out.
Assassins are good for more than that though. They also use a combo system like the rogues from WoW BUT they have to chain certain skills together in order to use them. Lead attack -> Off-hand Attack -> Dual Attack is the standard linkage of the skills. If you chain certain skills together that have do certain effects and have certain conditions, you can really dish out some uber pain. For example, a lead attack does a cripple effect, the off hand attack does a bleed effect if target is crippled, and the dual attack does a critical hit if target is bleeding.
As for ritualists, they are a mix bag. Like shaman from WoW, they have to summon spirits (instead of totems) to do their dirty. Rits (as they are nicknamed) have the ability to act as a healer so they are a good alt to the monk BUT they rely heavily on their spirits to boost their healing, putting them at a disadvantage since players have to fight near the spirits to be effective.
The cake is a lie... THE CAKE IS A LIE!!!!!