I've had the beef, sirloin, and vegetarian canned haggi from the Caledonian Kitchen, and liked them all.
I've ordered haggis in stomach and haggis links from The Oatmeal Savage. These were also good, except for the one that was delivered to the apartment rental office and sat there for a day before I found out. You would think that the word "PERISHABLE" on a white box would have gotten their attention, but ...
And to be fair, I have had BAD canned haggis. The taste, the texture, the after-effects - this was a bad haggis.

And you don't necessarily have to eat the full traditional meal. I've used leftover haggis as sandwich filler, shaped it into patties and ate it like a burger, even used it to make 'Scottish burritos.'
The last occasionally made for interesting reactions from my Mexican-American co-workers in El Paso - "Hey, that's a good smelling burrito! What is it?"
"Haggis with potatoes and garlic."
"Haggis?! Eeewwww!! ....... What's haggis?"
You would think guys who think boiled tripe and fried pork skins are good food would be a little more open-minded.