I'm a tourist from Hong Kong.
This is the worse experience I ever had:
The trip was scheduled
I was arrived 30mins earlier than the departure time at Venice.
Finally arrived at Milan, it was a cold, outdoor place. And I have noticed there are a 2hours delay, and we can do nothing but sitting on the bus station to wait for the bus.

The bus came eventually, I'm already missing 2hrs of my trip, after passing Genoa.
The bus had some issue about the engine and stop for almost 3 extra hour on the highway.
[it was Already 8:47am]
I was keep expecting there are a bus coming to pick up us, but nothing happened!!
The bus driver keep telling us the another bus are coming to pick us, we want to know when will it come, but he said.he don't know.
Then the repair truck came and we thought the bus will be fixed, but they only took our BUS out of the highway to another location.

Again, the driver telling us the another bus is coming but don't know how long it takes.
We finally arrive at Destination at 6:00pm, which is
10hr delay, we lost our whole day trip.
We missed our hotel check-in time, we miss some Spot we planned to go, we need to pay extra fee for Transportation.
After we back to Hong Kong, I try to let FlixBus to know how disappointed and upset we are.
They reply very slow, it takes a week for each email reply, feel like they don't care about their customer.
We mentioned that we are tourist, but end up they offered us a free ride. The matter is we would not go to Europe that frequently, This is how they offer us for ruining our trip.
For others who want to travel by Bus, please pay attention to this company - Flixbus.