The essential thing is that Twa Corbies is Scottish and cynical, Three Ravens is English and more naive. I used to prefer the cynical version, but, as Bob Dylan puts it, "I was older then, I'm so much younger now", and I think I find the naive way of seeing things more essentially true. But you pays your money and you takes your choice.

Anyway, here is a thread about the songs on the Mudcat

There are lots more - just type Twa Corbies into the supersearch (Digitrad and Forum search up towards the top of the index page on the left) and you get leads to all kinds of discussion about them.

You might need to be a registered member for that, I'm not sure. But that only takes about one minute to do, and unlike registering with lots of things on the net it doesn't mean you get unwanted emails from people trying to con you.