I presume you are talking about some sort of “sandwich” placement or “internship”, as I’ve never heard the phrase “Professional Experience Placement”.
We’ve engaged a couple in the past and one right now. Good students with the right work ethic, and who want to “prove something” (either in the hope of getting a job with you or to have some REAL demonstrable experience and a great reference) are good. The problem is that I would say that applies only to the top 20% of students. The rest, and in particular the bottom half, are a bloomin’ nuisance.
With the best students the hard bit is giving them something meaningful enough that they feel happy whilst straightforward enough that they don’t need 100% constant supervision, and not so “mission critical” that if they do cock it up you can redo it etc.
The student is usually looking to improve their job prospects, so that usually means they won’t be making tea. Although students and fresh graduates often are unrealistic about what “entry level” in their career path will involve. Somebody does have to do the hands on, mundane and boring stuff – and usually that is going to be the new guy.
Whether it is for 6 weeks, or a whole year I think it is quite important that there is some sort of clear plan/structure for them. Just like any employee they need to know who they report to and what is expected of them, but it also seems to be useful to work out a rough plan at the start and review progress periodically. However, all three have found it harder to cope with changes to the plan, things getting delayed or just not working as originally expected. This is probably not surprising because in the undergraduate world everything is timetabled and structured to run smoothly.
We’ve already agreed we will do it again, but we will control the selection process not the University!