Biggest advantage to the SuperNova is the ability to, rack the slide open and not automatically feed the next shell.
If you watch,,, Magpul a art of the tactical shotgun. You will see guys dumping full tubes out of their (870’s and 590’s) to be able to do a slug change over from buckshot. With your super nova all you do is press the no feed button rack her back pop in the slug and your good to go. .