If traveling during the next few weeks the best transportation is the bus. With 2,40 euros you reach Amalfi from Salerno. From Amalfi you can then reach Sorrento and Ravello easily with the bus too. If traveling in Juli/August i would not suggest bus, maybe ferry would be better (but ten times more expensive)
How about travelling in October?
Gonna be ok.
"Best" implies a value judgement, without knowing what is important to you for this decision it's hard to be helpful.
If lowest cost is your priority, the bus is the best fit.
If comfort and convenience are high on your list of priorities, the bus probably isn't a great fit.
You can also move around the cost by ferry.
At the high end (cost) you could hire a car service which gives you the ultimate flexibity to choose your sechdule and stops.
We took the Sita bus to Ravello 2 days ago from Salerno old town area and it was so full (packed with the aisle full) that the driver only picked up one single passenger after us. Mind you, there were about 10 people left on the side of the road that wanted to get on. This was at about lunchtime. The bus was running late too. It’s a very twisty road and goes very slowly - I think it was almost 2 hours to travel less than 30km. If you have any opportunity to avoid the bus, then avoid it at all costs. On another note - we walked down from Ravello to Amalfi in the afternoon and it was a lovely walk. We took the ferry back to Salerno. It was worth every cent.
You did that in the weekend, it is not always like that. Moreover if you want a place you just need to take the bus at the Vinciprova Station, i always find place there and the locals know that.