1) As mentioned, it depends on the degree, humanities based degrees tend to have more group work than science based degrees, although that is a broad generalisation
2) Depends on the tutor, sometimes yes other times no.
3) If you want a job done properly do it yourself. Personally, I prefer having a lazy group over an eager group who are hopeless, because at least then I can be in control and I can prevent people from doing stupid stuff. I know that sounds arrogant, but a lot of times at university (especially at my university) people have no clue what they are doing.
Group assignments are one of the most dreaded aspects of university and for good reason - they are mostly an irritating pain in the ass unless you have a group composed of your mates or people who are motivated and have a clue as to what they are doing (this is a hard group type to find). However, its important to remember that group assignments are a part of university because they a part of the workforce. At the end of the day, you will most likely be forced to work in groups when you go out in the workforce and you will probably encounter a few useless people. So its best to get used to it in uni before you cop it in the workforce.
Also just as a side note, the threat of peer review is useless. After all, if someone doesnt care enough to help you with their assignment, what makes you think that they will care about a peer review. A peer review is also useless if your group members do all their work but are hopeless - some members try and put in a genuine effort but the work they give you is awful. It's hard to give someone a bad review and possibly cost them marks if they put in effort. Finally, giving a person a bad peer review can create more trouble then its worth. I've seen bigtime "he said, she said" type feuds arising from peer reviews - its just easier to give everyone 100% and leave it at that. People might disagree with me over this post, but those are my observations.
