Ataru started out as a perverted lecher oblivious of anyone's feelings. I had the most fun watching watching him suffering throughout the series. And honestly, I had my share of perverted loser main characters throughout the years.
And To Love-Ru is quite funny, without resorting to reusing the same gags and clichés over and over again. Urusei Yatsura was also funny for its time but started at one point the introduce new character for repeating the same gags routine, which is annoying after a while.
Anyway, UY was good for its time, To Love-Ru is good for its time. In after RAAAAAAAAGE.