They're not evil or anything. They're just dreadfully inane and very..factory-produced. I'd probably consider them more harmless than Junie B. or Ivy and Bean, because there are no obnoxious attitudes, although they do play into the girly-princess-pinky-pretty stuff. I think DD built a lot of reading fluency with them, so there's that.

I agree that MTH is another option at this reading stage. A to Z Mysteries? I have other recs for young fluent readers in terms of age-appropriateness, but it depends on fluency.