The UK process is great if the student's goal is to gain a PhD. After approximately 3 years of running experiments, you present your hypotheses and gather together your results and try to make it look like these are related. If the goal is to have an academic career, this is not adequate. Graduating without having results that are good enough to publish in peer reviewed articles puts the UK student far behind others…
When I was an academic my university put great pressure on us to get our students out in under 3 years citing the UK system. Of course when we raised the problems the UK system (ie having our students graduate with no papers) would have on them we were told basically to shut up and do what ever it took to get the students out on time. It became pretty common for supervisors to write their students dissertation and for more senior researchers to 'gift' results to students to get them out on time.