Maybe Mr. Meaty is the worst Nick show, but that has one redeeming quality, it's promotion of meat and demotion of vegans. The X's is horrible, appalling, whatever, with no redeeming qualities.
The animation is gag-worthy. It's jagged and the holy grail of the standards that animation today. You know what, it makes the Replacements look like the Mona Lisa! The Replacements darn you! And that's saying something! I hate animation nowadays, anime and all. The only good animation left is Spongebob, FOP and Avatar, with a few others. And other greatly animated shows like Danny Phantom, American Dragon Jake Long and Kim Possible are cancelled, so that just leaves crap.
The acting is, okay, but their wasting it. Tom Kane, Wendie Malick and Patrick Warburton are great actors/actresses, but it is zapped by this mindless excuse for a show. The writing is horrible and the jokes are appalling.
And it's a complete ripoff of The Incredibles! I loved the Incredibles, but this is downright plagiarism! They are a family that has to keep a secret identity, they have a teenage daughter who wants to live normally and a younger son who loves having his powers/gadgets. The father loves his job as a superhero/spy and their mother is sweet and sensible. Sounds like it, no?
So waste your time on the Replacements or Cory in the House or even Phineas and Ferb, and save your mind for something else.