Yeah, i'm currently doing this unit at the moment.
The group assessments...well, it really depends on your group. If you get a dodgy group, then run for the hills : P
Personally, i thought it was allright...i think i'm sitting on a credit for it atm. We had some problems with a few group members being responsive (one was non existant, another moved back overseas). A lot of people weren't happy at the way the unit was arranged (ie doing the work with members from other campuses) But that really depends on the group. You might have people who are responsive and cooperative, you might not.
however, the group members all get a say on the marks of everyone else by evaluating them. I wouldn't say it's any harder or easier than other assessments (for similar subjects) If you break down the workload, it really isn't all that much.
~Tenni~