The Bartimaeus Trilogy is both funnier and better than both LotR and HP.
Anyway. I don't think you can compare those two series. LotR being somewhat epic in the genre of fantasy and very important to the early beginning of roleplaying, and HP being a modern tale of fate and magic.
Both tales have some faults and some goodies, but not really comparable, since they are too different, and have fans all around the world.
