Espiritu Santo or Tanna?

I have to make a difficult choice, which island to vist Espiritu Santo or Tanna this year May?

Both seems to be quite appelaing. I've been once just on Efatu for few days.

Espiritu Santo seems to have better accomodation options and nicer beaches, but Tanna offers volcano exoitics.

Anyone who 've been at both places, can help to make a choice please?

Tough choise for sure. If you are a diver, Santo is your place. There is nothing like diving the Coolidge at night. If you are not a diver, go to Tanna to visit a village, see the beautiful wild horses, and view the volcano. It's an experience you won't soon forget.

Depends what you are looking for.
I found Tanna more "exotic" overall, but for diving and beaches Santo is better.

I don't know what you're looking for, exactly. Both islands have aspects that appeal to different people.

Santo for scuba diving and white sand beaches. Besides these and the millenium cave, there was little else on Santo that I personally found very interesting.

Tanna is more exotic and has more of an "untouched" feeling to it. I found the locals much friendlier than on Santo and the landscape was absolutely gorgeous. The volcano was great but I equally enjoyed the cultural village tours. I term "cultural village tour" may sound kind of pedestrian but they were incredible. However, if you're looking to laze around on a beach Tanna isnt the place...the beaches were mostly jagged black rock, although there was excellent beach and snorkelling at Port Resolution.

If you go, I recommend Lonnoc Beach Bungalows on Santo and Leneai Palms Resort on Tanna.