It's hilarious, that is, if you're a fan of mockumentaries and the type of humor that is associated with them. Some friends of mine had watched it and told me how funny it was, then I watched it and thought it was really quite bland. Soon after I started watching NBC's "The Office" and fell in love with that show due to the type of humor that's in it. I then watched Blackballed again and finally could appreciate the humor.
In short, if you like The Office or mockumentaries, you'll like Blackballed.
PS: Eddie Reynolds is reason enough to watch it. Black Death! Black Death!