Maharal, in Derech Chaim, says that the machlokos of Hillel and Shammai were the purest form of l'sheim shomayim, in that there was nothing that they could have done differently to prevent them:
שהמחלוקת שלהם היה לשם שמים לגמרי. שלא תוכל לומר עליהם שום צד שלא לשם שמים, שאי אפשר לומר שאם היו מטריחים עצמם בהלכה לעמוד על הדבר, או ילכו לשאול, לא היה צריך להם המחלוקת
It seems that he's contrasting them with Beis Hillel and Beis Shammai, of whom the Gemara (Sanhedrin 88b) says לא שמשו כל צרכם, their machlokos were because they hadn't applied themselves as fully as possible to learn from their teachers.
(The editor's footnotes there, though, are unsure about this understanding, since some of the Maharal's phrasing there - such as the expression אלו ואלו דברי אלקים חיים that he quotes - is, in the original (Eruvin 13b), speaking of Beis Shammai and Beis Hillel.)