The rule of thumb I was given, by a very wise and experienced instructor, was that in a light twin the failure of one engine means that the other engine will take you all the way to the crash.
Some will climb on one engine, some won't, he said. Persuaded me to go for high-peformance singles rather than twins. I have no regrets on that score.
I've had my engine failure (are we only allowed one each under JAA?) in mid-channel - made it to land. That was in a single.