Mount Etna is fantastic but if you go, avoid going with Geo Etna Explorer.  It is a company of questionable practices.  They charge you 55 Euro just for a lift there, when there is a bus that does the same thing for 10 euro.  Their guides don't speak other than Italian and if you want to go to the top you have to pay an additional 25 euro for the funicular.  The spend most of the excursions taking you to shops and restaurants from which they make a commission and they try to sell you all kinds of things. You're better off, hiring a car or taking the bus.  You don't get to see much of the mount which is what you went there for in the first place.

These people only accept cash payments and if you ask them for a receipt they refuse to give it to you...