Spot on Neil. I believe that overall bookies and punters get the prices right for a race (it has been shown that horses win in proportion to their starting price). It is pointless following the same selections as everyone else, and most rating methods end up with very similar odds as has been pointed out here.

But remember too, a horse's rating price is just a measure of its chance of winning a race. A top rated horse with a rating of $3 say, in a market framed to 100% (in practice this most likely would be put up by the bookies as $2.50) indicates the horse has a 1 in 3 (33%) chance of winning, however, there is a 2 in 3 (67%) chance of the winner coming from one of the other horses.

The real skill in punting is to find the winner from the other 67% that most other punters overlook and where TAB overlays appear.