Engineer is working very well and supports the top parsing specs such as Bolt Caster/Bio Shell and Energy Auger/Electrocute/Mortar Strike.
Medic is also working extremely well, and has recently been changed to support the new changes regarding Quantum Cascade, (two casted abilities can be used at once). Medic telegraphs are also one of the easiest to hit multiple targets with.
Those two classes work the best from what I have tried.