This is a work in progress. I have 3 tunes in SL beta so far:
Kyrian Paladin
Night Fae Shaman
Night Fae Druid
They are all solid classes and fun to play. I have completed the Covenant starter quests and the first part of the campaign on all of them. I have unlocked all of the conduits on all 3. I have played mostly prot and a little ret on the pally, elemental and resto on the shaman and balance, feral and guardian on the druid. All three classes are solid and fun to play with full conduits, even in blue starter gear.
The Paladin and Druid are both solid tanks but I have to give the Paladin a slight edge there. The Ele shaman has good dps and is fun to play. Resto shaman is a solid healing spec, especially with conduits. The druid is powerful and versatile, it does everything well. The druids problem is that it has 4 specs and only 3 soul binds. The prot pally can solo almost anything except skull bosses. The druid is kinda squishy and has to switch to guardian for many boss or elite encounters. Kyrian and Night Fae Conduits and Covenant abilities seem well suited to the Paladin and Night Fae to the Shaman and Druid, especially the Druid. I would have to give the Kyrian/Paladin combo a slight edge on Conduits and Covenant abilities.
If I had to pick one class of the 3 right now as my main, it would be the Paladin. The Paladin inspires more confidence. The Pally rotations feel smoother, the Pally specs feel more polished. The Paladin conduits are all helpful and impactful.
My personal preference is Paladin >> Shaman >> Druid.