Here are my two cents...
Personally, I feel going to a university in person is usually much better for the educational process when compared to online courses.
However, I will toss this into the mix. (This really doesn't apply to the original poster, but I'll say it because I want to

) Some of the online meteorology courses, especially the MSU course is designed to work with other training received. Matter of fact... this is from the MSU website:
The OMP provides a student with a wide variety of meteorology courses. The program was designed to compliment the weather training received in the military. However, military meteorological training is not a requirement for the program.
The idea behind the MSU program is to help military mets who are stationed too far from an university offering a meteorology program and/or those military mets who are working shift work and cannot attend normal classes.
The degree is meant to help further the training we (military mets) have received plus the day-to-day experience we get working behind the desk. With that said, the degree is also "useful" for non-military mets, but it takes work. (Think of it this way... when I retire from the military after 20-30 years of service, while a MSU degree isn't the most desirable, I will have 20-30 years of
very diverse experience that will outweigh the degree anyway. The degree just fulfills the requirements)
If you take an online meteorology course with limited meteorology experience (ie, being a weather watcher/hobbyist), it will be rather difficult and an actual in-class course may be better. However, if you do have some meteorology background and you put forth the effort required, you should have no problems.