Patronsaint makes a good point about the effect of peer groups. This also feeds into the NSS (National Student Survey), by the way.
For various reasons I can't go into here, we happen to have a very aggressive and proactive widening participation policy on our course, so we take a wider selection of students than other research-intensive universities do (we are in the top 50, by the way). Some groups of students (and I really do mean some, certainly not all, but it's a noticeable minority) who score lower in terms of UCAS points, and where most students are the first in their families to go to university, are clearly poorly prepared for higher education, and basically expect university to be like school. They frequently talk about 'lessons', 'teachers' and 'homework', even after a couple of years with us, and seem to get hugely irritated if they aren't spoon fed information on pieces of A4 to memorise, as they are of the mindset that if they have to look information up in a book, it is because the lecturer has been too lazy to prepare a worksheet for them (seriously - I had one group of students in my former Very Highly Rated institution go as a deputation to the Dean because I asked them to do this, and they formally complained I didn't have any subject knowledge. The Dean then pointed out to them I had written a book and several papers on the topic, was an authority, and directed them to the library, which flummoxed them completely, apparently 
).
The attendance of these lower UCAS scoring students can be significantly poorer than other students, and they seem to expect to be chased up frequently in order to attend. When we tracked some of these students, we found that they were less likely to attend university regularly, and that there was a statistical correlation between their attendance, which was between 60-80%, and their marks for assignments, which were 10-20% lower than lower UCAS scoring students who did attend regularly - a difference of 1-2 degree classifications. Obviously we use various disciplinary and advisory measures to try to improve this and get the attendance message across, but ultimately the students are their own worst enemies in many cases. When we tracked what they were actually doing when they weren't at uni, it was things like social networking (not paid work as we expected). Indeed, this group spend in excess of 20 hours a week on Facebook alone, excluding the course or uni FB sites. Interesting stuff.
Their approach to academic work can be superficial in the extreme, especially during the first year, and they take it very, very personally if they are marked down for anything at all. Spelling, grammar and referencing are insurmountable problems for some of them, and we need to run extra GCSE-style classes in order for them to develop the ability to write essays and reports. It soon becomes clear that their impressions of their own abilities have been grossly inflated by the institutions they attended for years 12 and 13, as well as their AS/A Level courses.
Their presence on the course can have a darker side. In some more extreme cases, despite all our efforts, they display a strange tendency to bitch about the course in groups, and take their 'revenge' via poor student feedback, even though the university is providing a perfectly robust, well-run academic 'product', which suits all other types of students, and putting in the required resources for this particular group (including remedial school-type teaching where necessary, as outlined above, which is not exactly our remit). Their behaviour sits in contrast to the higher UCAS scoring students, who seem to be more upbeat and independent generally, and respond more effectively to our teaching and academic interventions. They are more likely to attend 85% or more of the time, are more likely to score grades in the 65%+ range (1st or good 2:1) and are more likely to become involved in student societies and groups whilst at university as well, meaning they start to develop good contacts for later life. This is where such students have an edge.
One good thing about the Browne review (possibly the only good thing) is that some of these students might be filtered out of highly academic courses where they are poorly equipped to thrive, and encouraged to study on higher level vocational courses whilst in the workplace, which ultimately might knock the edges off them faster than university can hope to, leading to better careers for them, and a happier experience for them as students. At the moment they are square pegs in round holes, and if I am really honest, a drain on our energies and resources at university.