How silly can a series about a fightin' butler be? Even sillier than it sounds. You'd have to dredge far and deep to find a morsel of seriousness amidst this glut of goof. Don't even bother looking to the usual suspects for substance. Hayate's home life might be hell, but his sociopathically self-involved parents aren't only treated as a running joke, they're never even actually shown. As for his up-and-down relationship with employer-cum-self-styled-romantic-interest Nagi, he's so absolutely clueless about her feelings (and she about his) that it really is more a gag than a romance. And his professional travails...well, any job where qualification involves wrestling a talking tiger and defeating an irritable caretaker robot (complete with missiles...for fending off stalkers of course) isn't exactly going to be a source of workplace drama.
Other than a knack for using cheap animation to humorous ends, there is nothing remarkable about Hayate's visuals. The backgrounds are rote, never anything more than simple backdrops. The character designs are mediocre at best, with bland lookalike faces and indeterminate physiques-forgettable in every conceivable way, and only distinguishable via their coloration and signature outfits. There's a certain overall pastel haziness, but it isn't marked or distinctive enough to count as a genuine look. The vast majority of movement is confined to flat horizontal or vertical movements across the frame. Movement through settings is confined to short bursts.
If you're hunting the market for a low-investment comedy that keeps the chuckles coming and never overreaches itself, then Hayate is your man; particularly if your anime trivia is up to snuff. It isn't without its worrisome trends -not the least of which is its rapid establishment of a potential harem- and its look is boring, but for now at least its sheer silliness (and its scene-stealing narrator) make it one of the more reliably amusing series out there.