A and C has hit the nail on the head. I made the mistake of thinking a young, keen low-hours instructor was the best for me when I started out with the PPL.
It was only later when he'd left for the airlines leaving me ill equipped to pass the test that I realised the big holes in my knowledge and training.
I was then the first student of another young instructor (who had several hundred hours already logged) and he turned out to be excellent. Between him and an older, grey-haired chap who'd been instructing for years I progressed to licence issue, sorting out problems with nav I didn't know were there and also adding a finesse to my flying.
It goes to show that experience counts, not necessarily the age of the instructor. And when you're forking out thousands of pounds for a service it pays to shop around, ask lots of questions and proactively choose the instructor you're comfortable with. Don't just go with whoever the school pushes on you.
Lunchmaster