What is the best Rehgar build now?

His Strong E build got nerfed a few time. Lot of players still seem to go with that one, other go W. I see a lot of different builds and I’m a bit confused which one is the best in general.

What is your favorite and most effective build?

It’s W build.
The major problem that I would love to see changed is that he needs to have mana tension.

Lightning Shield

50 Mana Cooldown: 8 seconds

Imbue an ally with lightning, dealing 64 damage a second to nearby enemies. Each enemy hit restores 2 Mana to Rehgar. Lasts 5 seconds.

1 Mana instead of 2, por favor.