The advantage of taking the pre-license course online is that you manage your time and avoid the commute.  On the other side, there are great advantages to attending the pre-license course on site, which have to do with the interaction with other future agents and having direct access to the instructor.  Most instructors of pre-license courses are highly experienced brokers, who are happy to share their personal experiences over the years. 

The online approach is mostly recommended for highly motivated individuals, who enjoy a quiet study atmosphere and are willing to study independently, while feeling free to ask questions of their online instructors.