I use chase view. The main reason being in past GTs i could see the back end spin out. But on bumper cam i found you only felt the back end slip out when it was too late to correct it. (Quite a big problem, because i always tune my cars to be very oversteery, although less so in GT5P)
Recently i have been trying out in-car view and it is much better than bumper view, because you can 'feel' the back end slipping out. I still need more practice with it, so i'm sticking to chase view for now. When i eventually buy a G25/G27 wheel i will switch to in-car view and never go back. I don't think using a wheel would work with chase view, it just doesn't look right and i bet it doesn't feel right either.