Having read some very positive posts about Swiss, I decided to try it out for a recent trip. I had 2 tickets, one Dublin-Zurich return (and everything went very smoothly on that, both ways), and the second was Zurich-Florence.

When I went to check in online for the 2nd flight, just after it opened, I was unable to change from a window seat, as the other seats were shown as occupied. Surprising, but maybe my ticket class didn't allow changes - it could have been clearer though.
Then, on boarding, my neighbour's hand luggage didn't fit under the seat and he boarded so late there was no overhead storage left. He was rather tall, and proceeded to place his case upright between his seat and the one in front, and straddle it. On top of this, he stacked his laptop case and a coat.
After the announcements, I expected he would make an effort to move them.
The cabin crew made no effort to deal with the situation, and apart from the major safety issue, I was confined to a very uncomfortable slot with gritted teeth, hoping for an early arrival.
This was not improved when, on a clear day (maybe a bit overcast) with no obvious turbulence, the captain said we were diverting to Pisa due to weather conditions in Florence, after circling it for 20 minutes. Over Pisa, another 20 minutes of circling before he said we were refused landing, and were proceeding to Bologna. There, very slow announcement service and a long delay before a coach took us back to Florence - 2 hours away. No offer of food, apology etc.
In fact, the landing announcement was something along the lines of 'thank you for flying with Swiss, we hope you enjoyed your flight'.
I didn't use the return half of the ticket.