Ever see what happens when you put a .308 through can of corned beef? Nothing but entertainment! Is canned corned beef better than SPAM? (I LOVE SPAM)
IMO it is much better. I had plenty of spam as a kid, not high on my list now.
The best canned corned beef comes from Australia and New Zealand. In the US the best place to find it is an Asian grocery store. PALM or OX AND PALM brands. Philippine grocery stores carry it, but they are not as common as Asian grocery stores.
http://www.amazon.com/Ox-Palm-Corned-Juices-11-5oz/dp/B005XB496W
Fry it up with a can of diced white potatoes and some fresh onions, yum.