I have no issues with canned beef, like I have no issues with canned tuna fish.
I just avoid canned food in general and opt for fresh stuff... but when push comes to shove, canned food is great.
SPAM really is one of my favorite canned food that it's a pantry staple in my house.
As per corned beef - straight out of the can is edible, but I much prefer Corned Beef Hash with eggs.
OP's corned beef + cheddar + water cracker is pretty enjoyable. I like to drop a bit of mustard on top though.