There is no debate. Those that have flown planes long enough, have probably been around to have seen a few engines go out on them....but don't take my word for it....
When a PC12 went down in the Sea of Japan, I am pretty sure everyone on board was very happy to only have had one engine, confident that the ditching to ensue really wasn't that big of a deal. And as they sat there in the life rafts freezing to death waiting for the SAR aircraft arrive, they all felt confident that single engine ops were really a great thing.
I wonder if Sully would have liked to have a few more engines before going into the Hudson? Nah....