Anyone take a bus in Italy?

We took Flixbus from Siena to Rome. It was very comfortable and inexpensive. I've also used Flixbus in other countries and found them consistent.

We took Flixbus from Siena to Bologna last year. It was comfortable and quick. We would gladly do it again.

We used the bus in Spain to get from Madrid to Granada and back, but I don't remember what line.

I too have used Flixbus in Germany and Austria. Registered online for my trips in advance of my trips. No problems, no complaints. Just be aware that to keep prices cheaper they stop near gas stations or parking lots, not necessarily a bus station. For example at Innsbruk the bus stop, closest to the train station was a few blocks away, near a gas station. Make sure you check your pick up and drop off points and don't assume they are at a central bus station. In Sicily I have used local bus services as well, travelling between cities, buying tickets right at the stops, at tobacco shops once at a gas station and also directly at bus station, but never in advance of my trip. Again, comfortable coaches, no problems. I cannot speak directly to bus service in Puglia or Sorento but I would be very willing to travel by bus if it fits my route and schedule.

Sure, they work fine and sometimes are more convenient.

Used FlixBus in Italy and service was great - clean, safe, on schedule. They have an easy to use app. Buy tix thru the app early to get best prices.

Flixbus user here as well. Rome-Siena-Rome. Got set up online the night before. In Rome the longer distance buses are about a block away from the local buses at the Rome train station. Took us a bit to find that out. That terminal was not as nice as the train station. But they had a convenience store for snacks & pop. And a bathroom (1 euro) Bus is comfortable with wifi. Dropped us off at a Burger King. Picked us up at a different stop about a block away. But it all worked out. There is a bathroom on the bus. The bus going outbound was pretty full. Coming back a bit more room. We'd use Flixbus again. It was comfortable & clean

It is not so much the comfort of the bus )every bus I have taken in Italy was perfectly fine) but the schedules. So, it would completely depend on where you need to go and how long you have to get there.
For getting place to place, sure use bus. But if you want to meander, I wold get a car--the driving in those parts is not challenging (though I would pick it up after Sorrento and upon arrival in Bari).

If travelling in Italy always use a reputable company Flixbus operates Europe wide. We used Itabus and were ripped off. They cancelled our booking and we've found since that they fail to refund people. Watch out, Itabus make money out of cancelling tourists bookings and making money out of it.

Tim