We have a very good system in place at our school for guiding students and their parents through the tricky process of applying to university. Last year, all bar five of the 120 students who applied via UCAS were successful in securing places with an additional 30 students electing to take a gap year. I suspect we will see an increasing number of students making a first application while in the Upper Sixth but with a game plan of putting in a more focussed bid the year after they have left. Certainly they offer a great deal to universities with an extra year's maturity and known A Level results especially where their Gap Year engages with opportunities to strengthen their application.
The best Gap Years are those with an opportunity to gain careers experience, academic breadth and the opportunity to take on independence and autonomy. If that includes an element of service either in the UK or overseas so much the better. Twenty years ago, my Gap Year led me to spend six months farming in the Falkland Islands, a job as a lambing shepherd in Sussex and two months exploring Europe through an Inter-Rail ticket. I was still seventeen when I left school and it was an incredibly valuable opportunity to 'grow up' away from school and home and left me much better equipped for life at university and beyond.
Gap Years have always been a little divisive with some seeing them as glorified holidays for public school layabouts. For a very amusing take on the Gap Yah rather than the Gap Year have a look at this video from YouTube.