What is it?
Comedy about a teenage boy who works off a ridiculous debt left to him by his parents by working as a butler for an even more ridiculously wealthy little girl.
What's good about it?
Great comedy packed full of diverse and likeable characters. Many episodes revolve around creative themes and settings. Packed full of clever references to other anime, manga and other copyrighted material. Makes a point of shamelessly providing service shots to fans. Light fare without many continuous plot stories.
What's bad about it?
Nothing really. It's 52 episodes long - absurdly long for solid, thin-plotted successful comedy- so it's understandable that some of the jokes and character reactions get somewhat predictable and repetitive but for the most part Hayate rises above that trap. Admittedly, some weeks were slower and less creative than others, which is always the challenge when your stories are episodic in length and you don't really follow a continuous plot.
The butler/maid setting has been used to a ridiculously obsurd degree in comedies in the last few years. However, I only hold that against series which are bad. If you're going to make a bad comedy, at least make it different so as to at least have novelty on your side. Hayate no Gotoku! was one of the most-watched series of 2007 and with that success will undoubtably come a whole new slew of maid/butler series in the coming anime seasons. However, I won't hold that against it because Hayate is a funny, accessible and pleasurable watch that I recommend for anyone looking for light-fare comedy. As always in these types of series, general knowledge of modern anime series is a plus for enjoyement purposes but not critical.
FYI- I've got a couple more reviews in my plate( Gundam 00 Season 1 & Bamboo Blade) for the upcoming week and I'm still in the process of picking my spring season lineup.