- Base-Breaking Character: Valkyrie, primarily due to being a case of Gender Bender for Ben. Some fans argue this shouldn't be possible, due to the Omnitrix maintaining the owner's gender, and the excuse to justify her being an exception is flimsy; others don't care, and enjoy her as an unique alien.
- Better Than Canon: Most people seem to agree that, despite the occasional spelling and/or grammatical error, this series as a whole is much more enjoyable than Omniverse due to maintaining Ben's Character Development from previous sequels, toning down the Denser and Wackier tone and better exploiting the various story elements.
- Broken Base: The multiple addition of new aliens for Ben to almost each episode. Some have voiced concern that there may end up too many of them, and the writer might end up so focused on adding new aliens he'll forget to flesh out the ones aleady there. Others like the new additions.
- Author has taken the concerns into account and has said he has a set amount now.
- Fan-Preferred Couple: One of the most prominent alterations is that Ben and Julie are still a couple, which stems from the author's favouritism towards the couple over the ones introduced in the show.
- Ron the Death Eater: Downplayed with Herve, Julie's boyfriend from Ben 10: Omniverse. Instead of actually suddenly turning evil, Herve is merely a student photographer of French Origin who happens to support Harangue. However, he is justified in that he doesn't like the fact that Ben attracts supervillains, not so much a personal grudge against Ben. The two are still somewhat civil around each other.
- Unexpected Character: Prisoner 775, named Valrean, appears as a prisoner in the Plumber HQ. as well as some other characters such as one of the Great One's former followers and some other minor characters making appearances.
YMMV / Ben 10: Guardians