Not sure there is much difference. A book is a book. If the teacher hangs all his lessons on the coursebook then you have a pretty good idea what to expect....grammar and gap fill exercises. My advice, buy the book, study in the comfort of your own home and save the euros. Some courses even advertise "we will study pages 87 to 154...."
You need to find out who is taking the course and then post his/her name on here and get feedback from students who have already had him/her as a teacher. From what I have heard, the university courses are mostly grammar based and the class sizes are quite large (especially part I II and III) so the students don't get a big opportunity to practise the language in the classroom. Class sizes get smaller the higher you go.
There is also this place
www.helsinginaikuisopisto.fiI did parts I-III there and also a conversation course. I had three different teachers in all, and all 3 were fine in different ways. The class sizes were reasonable (btwn 6 and 15 students) and we were expected to participate, especially in Part 3 and the conversation class.
HTH