After a quick search on FCO here, I was surprised that not much came up apart from the usual lounge access and connection questions.

I found the airport to be rather odd. The T5 terminal check-in area that's used by all of the U.S. legacy carriers looked a lot like a what you'd find at an airport in a third-world country. Sparse and utilitarian, like it used to be offices or a hangar.

After clearing security and passport control, you have to take a shuttle bus from the terminal to the concourses. On a separate note, I was also surprised that the border agent did not stamp my passport upon exiting the Schengen zone. I've seen border agents at least somewhat plausibly pretend to flip through a passport before stamping it. In this case, he barely opened it, probably not even to the photo page, and then passed it back to me.

The Alitalia lounge ("Casa Alitalia") in concourse G was modern and nice (including a made-to-order espresso bar and tasty and well-presented food buffet), but was way to small for the Saturday morning crowd. I had to wait 10 minutes for a seat to open up. The attendants were way too overzealous in picking up dishes, picking up my plate while I obviously was not finished. It happened so quickly I didn't even have time to protest. Perhaps this was their attempt to hurry people along to free up seats?

I arrived at the gate 5-10 minutes before boarding and it was a zoo. The gate had two signs: one that said "zones 2-3" and one that said "SkyPriority" with "zone 1" printed in the blue margin below the SkyPriority logo. This, combined with the unclear boarding announcements, resulted in chaos. When they announce "Delta One" and "Diamond medallion passengers" a hoard of passengers rushed towards the gate, many of whom were understandably confused zone 1 passengers. To make matters even worse, they announced SkyPriority boarding shortly after, surely before most Delta One passengers were able to board.