Betty (an attractively drawn, plain vanilla Ms. Nice) - attends school by day, but by night beams into a spacecraft where she fights evildoers (a selection of unremarkable aliens), aided by a good alien (who tries to be "wacky", but doesn't even end up as "annoying" - he only nails "meh") and a robot (a totally bland, personality free character who was apparently only included to finish off the space opera checklist). Powerpuff Girls has an imaginitive mixture: the tone and humour of a standard American cartoon with the settings and genre conventions of superhero comics and a light smattering of anime's visual style, wrapped up with cute characters. Atomic Betty has a single cute character inhabiting a totally uninspired universe.
The series is kind of a mess; action scenes are turned into incomprehensible messes by widescreen switches and split screening thrown in seemingly just for the heck of it, and humour ranges from unremarkable to stale, with a lot of reliance on overused cartoon stock gags. The cleverest piece of humour is the name of bad guy Maximus' I.Q's servant, Minimus P.U. (Portable Underling). That should tell you something about the show's writing.
Which brings me to the main point: Atomic Betty isn't all that funny. Not because the gags are bad - although that's often the case - but because there's very few of them. Despite the lighthearted tone, actual attempts to be funny between each episode's set-up and punchline are oddly sparse - apparently, Atomic Betty isn't intended to be an all-out comedy. As an action adventure-oriented series it is also let down, not only by the half-hearted action scenes and relatively slow pacing but by the fact that it simply can't be taken seriously. The show just doesn't know what it is.
It's still a fairly entertaining show, in an "alright-to-watch-if-there's-nothing-else-to-do-and-for-whatever-reason-you-can't-do-anything-besideswatch-TV" kind of way. It's rarely boring and it's rarely painful; it's just so enormously bland.