I know this thread is quite old, but maybe my reply will be still be useful.
I'm currently doing my Bsc Computing through UNISA. Their admin is almost non-existant. To give you an indication, for one of our modules, only one assignment has been marked. We are 2 months away from exams and the year started in March. :$
I would also say that almost half of our assignments were returned marked incorrectly, so you have to check that the lecturers have done their job correctly.
With that being said, the maths faculty and lecturer, is on the ball, replies to email, helps when you need assistance. There are one or two tutors who are very involved, but they are the exception, not the norm.
I have to agree with most of what LegionnaireJ has said. The course load is hectic, you will have to cut down on your social activities.
I work, have a family, so getting the balance correct is tricky. It is very doable and I try not to focus on the bad of UNISA, just do what is expected and if something needs sorting out, get in touch with someone and wait.....
Good luck.