We took the Mt Etna tour from Taormina last September. The bus ride wasn't terrible, since we got lots of info about the sights on the way and about Mt Etna. When we arrived at the base, we took a Unimog to 2400 ft, had a guide (really interesting information about the volcano) at that elevation with just a bit of walking (optional) The Unimog took us back to the cable car and we took that down.
Don't just take the cable car, you should take a tour so you can learn about the volcano. Just riding up and back down is not that much fun, and depending on the time of year, the cable car can get HOT. There were no windows to open up !
Seriously, there isn't a lot to see on Mt Etna, it's ALL ASH, dark thick layers of ash, no trees, no shade. BRING WATER and a sun hat.
Hubby said he wanted to hike down, but I nixed that. Without proper footwear and hiking poles,and water, no way to do that. it's very steep and the ash is hard to walk on.
you could take a www.gettransfer.com both ways and just pay for the tour on the mountain, but that might be quite a bit more $$ than getting a tour from Catania.