Hi! I'm currently an UMSL student in their part-time program. I just finished my first semester, and I really like it! Your first two classes are Pharmacology and Pathophysiology--and are tough. I heard a rumor that they may be changing the course schedules where those two classes are not taken together because they are both pretty difficult. I managed to get A's in both of them, but it wasn't easy.
I do work full time, and it is doable. The key is communicating with your professor. I had the same instructor for both courses, and she got the fact most of the class had families/work/etc., and was fine with taking tests early/late if necessary. We just had to let her know.
The advisors seem a bit disorganized to me, which worried me. But once I started the program, I don't have to deal with them much, and the instructors are really on top of things.
All-in-all it's a good program--I recommend it.