Hi Richard,
Like Ron says, check the presence of those shims. If, like the case was with mine, they are in fact there, you could try pulling the pads, cleaning the rear and the shims, and smearing a little coppaslip on them them before reassembling. Cured mine nicely. The one side used to whine, nice and loud.
Don't know of particular pads that are better than others, I just know some older types have a bit of a scratchy, grinding noise and feel to them when in use.
Tor